Friction-enhanced core surfaces for battery separator rolls and related methods

Abstract

Battery separator material rolls and related methods are disclosed. A battery separator material roll includes a core including an outer surface, a separator material wound around the core, and a friction enhancing surface on at least a portion of the outer surface of the core to prevent lateral movement of the separator material relative to the outer surface of the core.

Description

[0001] This application is a divisional application of the Chinese patent application with an application date of February 6, 2020, Chinese patent application number 2020800195446 and invention name “Friction-enhanced core surface of battery separator roll and related methods”, and this application claims priority to patent application No. 62 / 802,147 filed with the United States Patent and Trademark Office (USPTO) on February 6, 2019, the entire contents of which are incorporated herein by reference.

[0002] Copyright Notice

[0003] ©2020 Amtek Research LLC. A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the U.S. Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. Technical Field

[0004] The present invention relates to a battery separator for lead-acid batteries, and more particularly to a separator winding core having a friction-enhancing surface on the core that limits slippage of the separator winding on the core and allows for smooth release when fully unwound. Background Art

[0005] Valve regulated lead acid (VRLA) and flooded lead acid are two different types of commercially available lead-acid battery designs. Both types include adjacent positive and negative electrodes separated from each other by a porous battery separator. The porous separator prevents electrical shorting between adjacent electrodes and provides a reservoir for electrolyte. This separator is formed from a material that is sufficiently porous to allow electrolyte to reside in the pores of the separator material, thereby allowing ionic current to flow between the adjacent positive and negative plates.

[0006] The first type of lead-acid battery, VRLA, typically includes an absorbed glass mat (AGM) separator composed of microglass fibers. Although AGM separators offer high porosity (>90%), low ionic resistance, and uniform electrolyte distribution, they are relatively expensive. In addition, AGM separators exhibit low puncture resistance, which is problematic for two reasons: (1) an increased incidence of short circuits, and (2) increased manufacturing costs due to the brittle nature of the AGM sheet. In some cases, battery manufacturers choose thicker, more expensive separators to improve puncture resistance, despite recognizing that ionic resistance increases with thickness.

[0007] The second type of lead-acid battery, the flooded battery, is characterized by the absorption of only a small portion of the electrolyte into the separator. Flooded cell battery separators typically include porous derivatives of cellulose, polyvinyl chloride, organic rubber, and polyolefins. More specifically, microporous polyethylene separators are commonly used due to their ultrafine pore size, which inhibits dendritic growth while providing low ionic resistance, high puncture strength, good oxidation resistance, and excellent flexibility. These properties facilitate sealing the battery separator into a pocket or envelope configuration into which the positive or negative electrode can be inserted.

[0008] Recently, enhanced flooded batteries (EFBs) have been developed to meet the high cycling requirements of “start-stop” or “micro-hybrid” vehicle applications. In such applications, when the car comes to a stop (for example, at a traffic light), the engine is shut off and then restarted. The advantage of a “start-stop” vehicle design is that it results in reduced CO2 emissions and better overall fuel efficiency. A major challenge with “start-stop” vehicles is that the battery must continue to provide all electrical functions during the stop phase while being able to supply enough current to restart the engine at the required moment. In such cases, the battery must show higher performance in terms of cycling ability and recharging ability compared to traditional flooded lead-acid battery designs.

[0009] Most flooded lead-acid batteries include a polyethylene separator. The term "polyethylene separator" is somewhat of a misnomer, as these microporous separators require a significant amount of precipitated silica to be adequately wetted by the acid. The volume fraction of precipitated silica and its distribution within the separator generally control its electrical properties, while the volume fraction and orientation of the polyethylene within the separator generally control its mechanical properties. The porosity of commercial polyethylene separators typically ranges from 50% to 65%.

[0010] The primary purpose of the polyolefin included in the separator is to (1) provide mechanical integrity to the polymer matrix so that the separator can be encapsulated at high speeds, and (2) prevent grid wirepuncture during battery assembly or operation. Therefore, the hydrophobic polyolefin preferably has a molecular weight that provides sufficient molecular chain entanglement to form a microporous network with high puncture resistance. The primary purpose of the hydrophilic silica is to increase the acid wettability of the separator network, thereby reducing the electrical resistivity of the separator. In the absence of silica, sulfuric acid will not wet the hydrophobic network and ion transport will not occur, resulting in battery failure.

[0011] In the manufacture of polyethylene separators, precipitated silica is typically combined with polyolefins, process oil, and various minor ingredients to form a separator mix. This mix is then extruded through a sheet die at elevated temperatures to form an oil-filled sheet. The oil-filled sheet is calendered to the desired thickness and profile, and most of the process oil is extracted. The sheet is dried to form a microporous polyolefin separator and cut into appropriate widths for a specific battery design. The separator can be wrapped around a core and rolled into a roll for easy transportation and use during battery manufacturing.

[0012] When manufacturing batteries (e.g., lead-acid batteries), encapsulation equipment unwinds the separator material from a roll of battery separator material, cuts the separator material, forms an "envelope" from the separator material, inserts the battery electrodes into the envelope, and seals the edges to form the electrode package. The electrode packages are stacked so that the separator acts as a physical separator and electronic insulator between the positive and negative electrodes. The electrolyte is then introduced into the battery stack to promote ion conduction within the battery.

[0013] Proper assembly of batteries typically involves careful control of the direction and rate at which the separator material is fed into the packaging equipment to avoid equipment failures due to misfeeding of the separator material. This involves installing the roll to allow the separator material to unwind freely from the roll and be fed into the packaging equipment. Forming the roll to achieve this requires the use of a sheet of battery separator material on a roll that is wound around the outer surface of the cardboard core. The side edges of the wound roll of separator material are aligned to form a substantially level side surface centered between the outer edges of the core.

[0014] Winding a sheet of diaphragm material to form and maintain flush side surfaces confined between the outer edges of the core is challenging for at least two reasons. The first is that the diaphragm material tends to slide in the axial direction of the core as the roll is wound, transported, and unwound. The second is that ribs embossed in the diaphragm material cause it to oscillate, thereby causing the centerline of the diaphragm material to move axially as the roll increases in size, as its ribbed layers come into contact with each other.

[0015] Figure 1-Figure 2 Shown is a roll of separator material that can be used in battery manufacturing. Figure 3-Figure 4 A roll of separator material is shown that is unusable for battery manufacturing.

[0016] Figure 1 Shown is a perspective view of a roll 100 including battery separator material 102 wrapped around a core 104 and mounted on a portion of an encapsulation machine 106 . Figure 2 Shown Figure 1 A common problem encountered in battery manufacturing is the slippage of the battery separator material relative to the core as it is unwound from the roll. One result of this slippage is lateral migration of the separator material on the core (i.e., movement in the axial direction of the core). Figure 3 and Figure 4 An example of this phenomenon is shown in Figures 100, which show that the separator material 102 in the roll 100 has moved during winding so that the separator material 102 is no longer confined between the ends of the core 104. In addition, when the separator material is almost fully unwound, the embossed ribs tend to cause the remaining rolled portion of the separator material to move axially relative to the core. This misalignment can cause the separator material to be misfed into the encapsulation stage of the machine, thereby hindering or preventing the normal operation of the machine. As a result, manufacturing interruptions and damage to the separator material, other battery materials, or battery manufacturing equipment may occur.

[0017] One way to prevent movement is to adhere the membrane material to the core, for example with tape. This is an unsuitable solution for many enveloping machines. Attaching the proximal end of the membrane material to the core with tape or other adhesives often results in undesirable tugging or recoil on the material being fed into the machine when the roll is fully unwound. Tugging and / or recoil on the membrane material results in misalignment of the membrane material during the enveloping process. Therefore, there is a need for an effective solution to movement that does not have such adverse consequences. Summary of the Invention

[0018] Disclosed herein are friction-enhancing core surfaces and related methods for battery separator rolls. In a preferred embodiment, one or more friction-enhancing materials, such as strips or sleeves of sandpaper or rubber, are attached to the surface of a core to be used for winding a battery separator material roll. By increasing the frictional resistance between the core and the separator material to at least 1.75 times, such as at least 2 times, at least 3 times, or about 2-3 times, the friction-enhancing material reduces the likelihood of the separator material moving away from the core. However, the friction-enhancing material allows the separator material to be released from the core without pulling or recoil (i.e., maintaining sufficient release characteristics). In some embodiments, the surface of the core itself may include a friction-enhancing surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] To facilitate identification of the discussion of any particular element or action, the most significant digit in a reference number refers to the figure number in which the element is first introduced.

[0020] Figure 1 is a diagrammatic perspective view of a roll of battery separator material, which is an example of the prior art.

[0021] Figure 2 for Figure 1 Side view of the roll.

[0022] Figure 3 is a pictorial perspective view of a prior art roll of battery separator material illustrating movement of the battery separator material relative to a core around which the material is wound.

[0023] Figure 4 for Figure 3 Different pictorial perspectives of volumes of the prior art.

[0024] Figure 5 is a schematic diagram of the core of a roll of battery separator material, according to some embodiments.

[0025] Figure 6 An image of the test device used in the experiments of Example 1 is drawn. DETAILED DESCRIPTION

[0026] Provided herein are friction enhancing core surfaces for battery separator rolls and related methods. As used herein, the term "friction enhancing" refers to a property of a material or surface on a core that increases the frictional resistance between the core and the battery separator material compared to a core without the material or surface, but at the same time maintains sufficient release properties of the core (i.e., the battery manufacturing equipment is not subjected to pulling and / or recoil when the battery separator material roll reaches the end and leaves contact with the friction enhancing material or surface on the roll). According to a preferred embodiment, the friction enhancing surface can be provided by a material having friction enhancing properties attached to the outer surface of the core. As used herein, "friction enhancing material" includes solids, liquids, gels, pastes, and combinations thereof that can be attached, applied, or otherwise fixed to the core to provide a friction enhancing surface. For example, the friction enhancing material can be in the form of a sleeve or band that surrounds the outer surface of the core. Preferably, the friction enhancing material is a band of material applied to the outer surface of the core.

[0027] The friction-enhancing surface reduces the likelihood of the separator material moving off the core by increasing the friction between the core and the separator material, compared to a core without the friction-enhancing surface. In some embodiments, one or more strips of friction-enhancing material are attached to the surface of the core that will be used to wind the battery separator material thereon. In certain embodiments, the strips of friction-enhancing material comprise sandpaper strips. In some embodiments, the surface of the core itself may include or be modified to include a friction-enhancing surface.

[0028] Figure 5 is a perspective view of a core 500 contained in a roll of membrane material according to some embodiments. The core 500 includes a base core 502 including an outer surface 506 having a base static friction coefficient μ b-s and matrix dynamic friction coefficient μ b-k The core 500 also includes a friction enhancing material 504 located on or secured to an outer surface 506 of the base core 502. The friction enhancing material 504 includes a friction enhancing surface 508 facing the core 500. The friction enhancing surface 508 has an enhanced coefficient of static friction. μ e-s , which is greater than the basic static friction coefficient of the outer surface 506 of the base core 502 μ b-s , such as at least 1.75 times, at least 2 times, or about 2 to 3 times. The friction-enhancing surface 508 also has an enhanced coefficient of kinetic friction. μ e-k , which is greater than the basic dynamic friction coefficient of the outer surface 506 of the base core 502 μ b-k , such as at least 1.75 times, at least 2 times, or about 2 to 3 times.

[0029] The friction enhancing surface or material preferably provides a maximum kinetic coefficient of friction (as measured using the method of Example 1) of at least about 0.8, for example, about 0.8 to about 1.2, to the diaphragm material (back surface, faceted surface, or both). The term "maximum" is to be understood not as an upper limit on the kinetic coefficient of friction, but rather as the maximum value of the coefficient of friction obtained during the friction test. Thus, for example, at least 0.8 would be a desired minimum value for the maximum kinetic coefficient of friction.

[0030] The friction enhancing material preferably provides the membrane material (back side, faceted side, or both) with an average kinetic coefficient of friction of at least 0.6, such as from about 0.6 to about 1.0.

[0031] As used herein, the term "static friction coefficient" (sometimes denoted as " μ s ” or some variation thereof) refers to the friction force (sometimes expressed as “ Ff ”) experienced by an object at rest relative to a surface and the normal force (sometimes denoted “ F n ")(exist Figure 3 , represented by arrows in the figure, and imposed by the surface on the object) F f = μ s F n For example, when the diaphragm material is wound around the core 500, tension in the diaphragm material and / or other forces (e.g., gravity) cause the diaphragm material to exert an inward force on the core 500. In turn, the core 500 exerts a normal force outward on the diaphragm material to balance the inward force exerted by the diaphragm material. As long as any force applied to the diaphragm material parallel to the outer surface 506 of the core 500 does not exceed the friction force, the diaphragm material will not be affected by the friction force. F f = μ s F n , the diaphragm material remains stationary relative to the core 500.

[0032] As used herein, the term "dynamic friction coefficient" (sometimes denoted as " μ k ” or some variation thereof) is the difference between the frictional force (experienced by an object moving relative to a surface) and the normal force (exerted by the surface on the object) ( F f = μ k F n ) associated with the constant. For example, if the force on the diaphragm material causes the diaphragm material to slide relative to the core 500 (e.g., exceeding ( F f = μ s F n )), while the diaphragm material remains in motion relative to the core 500, the friction force is given by ( F f = μ k F n ) is given.

[0033] exist Figure 3In the example of FIG, the presence of friction enhancing material 504 increases the overall coefficients of static and kinetic friction of core 500 relative to outer surface 506 of separate base core 502. As a result, during the winding and unwinding processes, the diaphragm material is less likely to move laterally relative to core 500. Furthermore, even when the diaphragm material does move laterally relative to core 500, the sliding may cease more quickly than without friction enhancing material 504, which may prevent the diaphragm material from moving laterally and completely off core 500.

[0034] The friction enhancing material 504 has sufficient release characteristics so that when the battery separator material roll reaches its end and leaves contact with the friction enhancing material 504, the battery manufacturing equipment is not subjected to pulling and / or recoil. Preferably, the friction enhancing material 504 does not include an adhesive on its outer surface. The friction enhancing material 504 can be attached to the outer surface 506 with an adhesive; however, the adhesive does not contact the battery separator material rolled onto the core 500.

[0035] The base core 502 may have a hollow cylindrical shape, for example Figure 5 The shape shown, or some other shape (e.g., a solid cylindrical shape, a flat shape, a non-cylindrical shape, etc.). The base core 502 can include any of a variety of materials. For example, the base core 502 can include cardboard, a synthetic polymer (e.g., plastic), metal, wood, or any other material suitable for supporting a roll of diaphragm material. In some embodiments, the friction enhancing material 504 can include the same material as the base core 502. As a non-limiting example, the friction enhancing material 504 can be formed directly from the base core 502 itself by texturing the outer surface 506 of the base core 502. In some embodiments, the friction enhancing material 504 is a material separate from the base core 502 and is secured to the outer surface 506 of the base core 502 (e.g., using an adhesive, a staple, a tack, a nail, a rivet, or other securing mechanism). In some embodiments, the base core 502 itself may include a friction enhancing material, in which case sufficient friction may be added across the outer surface 506 to prevent lateral movement of the diaphragm material in the absence of the friction enhancing material 504 .

[0036] Figure 5A single portion of the outer surface 506 of the base core 502 is shown including the friction enhancing material 504. However, the outer surface 506 of the base core 502 may include multiple areas of the friction enhancing material 504 or may even be completely covered by the friction enhancing material 504. Figure 5 Also shown is a rectangular strip of friction enhancing material 504 on the outer surface 506 of the base core 502. However, the outer surface 506 may include friction enhancing material 504 in one or more different shapes other than rectangular (e.g., a triangle, an octagon, a circle, an oval, another polygon, an irregular shape, etc.) and sizes. Preferably, the strip of friction enhancing material or other oblong shape of friction enhancing material is disposed on the outer surface 506 at an angle, such as from about 30° to about 60°, such as about 45°, to the centerline of the center roll (i.e., the direction in which the diaphragm material will be pulled when unwound from the roll). However, as Figure 5 As shown, the angle may also be about 0° (ie, parallel to the pulling direction). Alternatively, the angle may be about 90 degrees (ie, perpendicular to the pulling direction).

[0037] Problems associated with winding and unwinding ribbed battery separator material may also occur with other sheets that include longitudinal ribs on at least one surface. Thus, in one embodiment, a method of rolling a ribbed material includes providing a core having an outer surface having a cylindrical shape, the width of the outer surface being defined by an outer edge (e.g., such as base core 502). As described above, a friction enhancing surface is formed on at least a portion of the outer surface of the core. The width of the core is selected so that the width of the continuous sheet of ribbed material is equal to or less than the width of the core. The ribbed material on the outer surface of the core is sufficiently aligned so that the outer edge of the core is flush with or extends beyond the outer edge of the ribbed material (e.g., the ribbed material is preferably centered between the outer edges of the core). The ribbed material is frictionally engaged with the friction enhancing surface. The ribbed material is wrapped around the outer surface of the core under tension. The frictional engagement between the core and the first loop of ribbed material helps to maintain the alignment of the ribbed material on the roll as the entire roll is wound. This helps the side edges of the wound roll have substantially flush side surfaces centered between the outer edges of the core (ie, the outer edges of the ribbed material are flush with or within the boundaries defined by the outer edges of the core).

[0038] In the case of battery separator materials, the ribbed material typically has ribbed sides and a flat backside. The flat backside can be wrapped around the outer surface of the core. Alternatively, the ribbed surface can be wrapped around the outer surface of the core. In particular, the ribbed material can have ribs on at least one surface of the ribbed material oriented longitudinally with respect to the sheet.

[0039] A well-wound roll of battery separator material is beneficial to the battery manufacturing process. Therefore, in one embodiment, the battery manufacturing process includes providing a roll of battery separator material wound as described above, which has a friction enhanced surface on at least a portion of the core (i.e., the side edges of the wound roll have substantially flush side surfaces centered between the outer edges of the core). The frictional engagement between the core and the initial loop of battery separator material helps prevent lateral movement of the roll as it is unwound and fed to battery manufacturing equipment, such as encapsulation equipment. Beneficially, because the battery separator material is not taped or otherwise adhesively secured to the core, when the roll is exhausted, the remaining portion of the battery separator material can be fully unrolled and released from the core without the battery manufacturing equipment exerting a pulling or recoil effect on the battery separator material. Therefore, interference in the battery manufacturing process can be avoided.

[0040] Likewise, a second roll of battery separator material wound as described above, having the benefit of a friction-enhancing surface on at least a portion of the core, can be supplied to battery manufacturing equipment with minimal shutdown of the battery manufacturing process. The end of the first roll can be secured to the beginning of the second roll with tape or other means.

[0041] Example 1

[0042] like Figure 6As shown in Figure 1, the frictional interaction between different core surface materials and diaphragm materials was tested. The cardboard core was cut, unfolded, and placed on a steel sheet as a flat rectangular surface. A 1 inch (2.54 cm) wide strip of test material was attached to the cardboard at a 45° angle to the direction in which the diaphragm material sample would be stretched. At the beginning of the test, the test material strip was aligned with the front face of the diaphragm material sample. A small piece of double-sided tape and magnets on the edges were used to secure the test material strip in place. A 4" x 2" sample of diaphragm material was attached to the underside of a weighted block and placed on the cardboard. The weighted block was connected to a Mark-10 model M5-5 force gauge. The total weight of the combined weighted block and diaphragm material sample was 414.6 to 414.7 grams. The test speed was approximately 8.2 mm / second (or approximately 490 mm / minute). Testing was conducted with the cardboard core itself, two types of sandpaper ("US" = 80 grit, "ESA" = 100 grit), and two types of rubber - nitrile and latex (from rubber gloves).

[0043] The ribbed sides and backsides of two different types of separator materials ("STD" = standard and "LR" = low resistance) were tested. The STD was an ENTEK PE separator with a GE profile, 162 mm wide, a backweb thickness of 0.25 mm, and a total thickness of 1.3 mm. The LR was an ENTEK LR separator with a GE profile, 162 mm wide, a backweb thickness of 0.25 mm, and a total thickness of 0.8 mm. The GE profile has ribbed sides and a flat backside. The ribbed side consists of a primary rib and a secondary rib (the difference between the backweb thickness and the total thickness is the height of the primary rib relative to the upper surface of the backweb).

[0044] Each combination of test material (or core itself), diaphragm material sample, and diaphragm side was tested six times. The maximum and average forces observed during the pull were recorded and used to calculate the coefficient of friction for each combination. Without wishing to be bound by theory, the maximum and average coefficients of friction are considered to be the maximum and average coefficients of kinetic friction, respectively. The results are shown in Table 1 below.

[0045]

[0046] Table 1. Force (in Newtons) applied when pulling different battery separator materials across a test surface at a constant rate. The maximum and average forces observed during the pull are shown, along with the coefficient of friction calculated based on each force value. Each value is the average of six tests.

[0047] It will be apparent to those skilled in the art that many changes can be made to the details of the above embodiments without departing from the basic principles of the invention. Therefore, the scope of the present invention should be determined solely by the appended claims.

Claims

1. A battery separator material roll comprising: a core, the core comprising an outer surface, the core comprising a paperboard core; a battery separator material wound around the core, the battery separator material comprising a polyolefin-based separator material; as well as a friction enhancing surface covering at least a portion of the outer surface of the core to prevent lateral movement of the battery separator material relative to the outer surface of the core, the friction enhancing surface increasing the frictional resistance of the battery separator material on the core by at least 1.75 times compared to a core without the friction enhancing surface while maintaining sufficient release properties of the outer surface of the core, wherein the friction enhancing surface comprises a friction enhancing material comprising a sandpaper sleeve or a sandpaper strip, the friction enhancing material being separate from the outer surface of the core and attached to the outer surface of the core using at least one of an adhesive, one or more staples, or one or more tacks, the sandpaper strip being attached at an angle of about 30° to about 60° to the direction in which the separator material will be pulled when unwound from the roll; The maximum kinetic friction coefficient between the friction enhancing surface and the battery separator material is 0.8 to 1.

2.

2. The roll of claim 1 wherein the battery separator material is ribbed.

3. The roll of claim 1 wherein the battery separator material comprises a ribbed side and a flat side, the flat side being wrapped around the core.

4. The roll of claim 1, wherein the friction enhancing surface increases the frictional resistance of the battery separator material on the core by 2 to 3 times compared to a core without the friction enhancing surface.

5. A battery separator material roll comprising: a core, the core comprising an outer surface; a battery separator material wound around the core; as well as a friction enhancing surface covering at least a portion of the outer surface of the core to prevent lateral movement of the battery separator material relative to the outer surface of the core, the friction enhancing surface increasing the frictional resistance of the battery separator material on the core by at least 1.75 times compared to a core without the friction enhancing surface while maintaining sufficient release properties of the outer surface of the core, wherein the friction enhancing surface comprises a friction enhancing material comprising a sandpaper sleeve or sandpaper strip, the friction enhancing material being separate from the outer surface of the core and attached to the outer surface of the core using at least one of an adhesive, one or more staples, one or more tacks, one or more nails, or one or more rivets, the sandpaper strip being attached at an angle of about 30° to about 60° to the direction in which the separator material will be pulled when unwound from the roll.

6. The roll of claim 5, wherein the friction enhancing material further comprises a rubber material.

7. The roll of claim 5, wherein the core comprises a cardboard core or a plastic core.

8. The roll of claim 5, wherein the coefficient of static friction at the friction enhancing surface or the coefficient of kinetic friction at the friction enhancing surface is two to three times the coefficient of static friction or the coefficient of kinetic friction, respectively, of the outer surface of the core without the friction enhancing surface.

9. The roll of claim 5, wherein the friction enhancing surface increases the frictional resistance of the battery separator material on the core by 2 to 3 times compared to a core without the friction enhancing surface.

10. The roll of claim 5, wherein the friction enhancing surface provides the battery separator material with a maximum kinetic coefficient of friction of at least 0.

8.

11. The roll of claim 5, wherein the friction enhancing surface provides the battery separator material with an average kinetic coefficient of friction with the battery separator material of 0.6 to 1.

0.

12. The roll of claim 5, wherein the battery separator material comprises a polyethylene separator material.

13. A method for manufacturing a battery, the method comprising: A first roll of battery separator material is provided, comprising: a first core comprising an outer surface and having an outer edge, the first core comprising a paperboard core; a first battery separator material having an outer edge having the same or narrower width as the first core and aligned on the outer surface of the first core sufficient so that the outer edge of the first core is flush with or extends beyond the outer edge of the first battery separator material; and a friction enhancing surface covering at least a portion of the outer surface of the first core, the friction enhancing surface being adapted to prevent lateral movement of the first battery separator material relative to the outer surface of the first core while maintaining sufficient release properties of the outer surface of the first core, the friction enhancing surface comprising a sandpaper sleeve or sandpaper strip being separate from the core and attached to the core using at least one of an adhesive, one or more staples, one or more tacks, one or more nails, or one or more rivets, the sandpaper strip being attached at an angle of about 30° to about 60° to the direction in which the separator material will be pulled when unwound from the roll; unwinding a portion of the first battery separator material from a first roll and supplying the portion of the first battery separator material to a battery manufacturing device while maintaining an outer edge of the remaining portion of the first battery separator material flush with or within an outer edge of the first core; and The remaining portion of the first battery separator material is unfolded and released from the first core without pulling on the first battery separator material, without causing recoil within the first battery separator material, or both.

14. The method according to claim 13, further comprising: Providing a second roll of battery separator material comprising: a second core comprising an outer surface and having an outer edge; a second battery separator material having an outer edge having the same or narrower width as the second core and positioned on the outer surface of the second core sufficiently that the outer edge of the second core is flush with or extends beyond the outer edge of the second battery separator material; and a friction enhancing surface covering at least a portion of the outer surface of the second core, the friction enhancing surface being adapted to prevent lateral movement of the second battery separator material relative to the outer surface of the second core while maintaining sufficient release characteristics of the outer surface of the second core; A portion of the second battery separator material is unrolled from the second roll and supplied to battery manufacturing equipment while keeping the outer edge of the remaining portion of the second battery separator material flush with or within the outer edge of the second core.

15. The method according to claim 13, wherein supplying the portion of the second battery separator material to the battery manufacturing equipment includes overlapping or overlapping the end of the first battery separator material released from the first core with the beginning end of the second battery separator material to continue supplying the battery separator material to the battery manufacturing equipment.

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