Techniques and apparatuses are described that anchor a battery cell to a flexible battery pouch, both of which are included in a battery pack. In some implementations, based on an external force (e.g., impact force), an internal mass of the battery cell may push through the flexible battery pouch due to a movement of the battery cell relative to the flexible battery pouch. The disclosed techniques and apparatuses are directed to anchoring the battery cell to the battery pouch by including a plurality of anchors in an adhesive layer included in the battery pack. The plurality of anchors is configured to create friction points against movement of the battery cell relative to the flexible pouch.

SUMMARY

Techniques and apparatuses are described that anchor a battery cell to a flexible battery pouch, both of which are included in a battery pack. In some implementations, based on an external force (e.g., impact force), an internal mass of the battery cell may push through the flexible battery pouch due to a movement of the battery cell relative to the flexible battery pouch. The disclosed techniques and apparatuses are directed to anchoring the battery cell to the battery pouch by including a plurality of anchors in an adhesive layer included in the battery pack. The plurality of anchors is configured to create friction points to reduce movement of the battery cell relative to the flexible pouch.

In aspects, the battery cell consists of a set of layers wound in a jellyroll assembly. The set of layers includes an insulator layer, a cathode layer, an anode layer, and a separator layer disposed between the cathode layer and the anode layer. An anchoring system configured to anchor the battery cell to the flexible pouch includes the adhesive layer. The adhesive layer includes a first surface configured to contact an outer surface of the battery cell and a second surface opposite the first surface. The second surface includes the plurality of anchors configured to create friction points against movement of the jellyroll assembly relative to the flexible pouch.

This Summary is provided to introduce simplified concepts for a battery cell to battery pouch anchoring system, which is further described below in the Detailed Description and is illustrated in the Drawings. This Summary is not intended to identify essential features of the claimed subject matter, nor is it intended for use in determining the scope of the claimed subject matter.

The use of same numbers in different instances may indicate similar features or components.

DETAILED DESCRIPTION

Overview

This document describes techniques and apparatuses directed to anchor a battery cell to a flexible battery pouch. In aspects, the battery cell is a set of layers including an insulator layer, a cathode layer, an anode layer, and a separator layer disposed between the cathode layer and the anode layer. The set of layers is wound in a jellyroll assembly and enclosed by a flexible pouch. The jellyroll assembly is adhered to the flexible pouch by an adhesive layer disposed within the flexible pouch between the flexible pouch and the jellyroll assembly. A pair of electrically conductive tabs are physically connected through the flexible pouch to the cathode and anode layers. The flexible pouch is vacuum-sealed and filled with an electrolytic solution. Altogether, the jellyroll assembly, the adhesive layer, the flexible pouch, and the pair of tabs form a battery pack.

As battery pack dimensions increase, and thus the internal jellyroll assembly becomes more massive, it is increasingly challenging for the battery pack to pass reliability drop and tumble tests. The battery pack can fail when the internal jellyroll assembly pushes through the sealed flexible pouch based on an impact force received when the battery pack, or the device in which the battery pack is installed, is dropped onto a surface (e.g., the ground). This failure mechanism is due to a movement of the jellyroll assembly relative to the flexible pouch and, in some cases, is exacerbated at weak points where the electrically conductive tabs exit the flexible pouch. The failure mechanism can result in a loss of the electrolytic solution, rendering the battery pack useless. Additionally, the set of layers in the jellyroll assembly can move relative to each other, potentially resulting in an electrical short between the cathode layer and the anode layer. The electrical short can cause more severe damage to the battery and a device incorporating the battery.

The techniques and apparatuses described herein are directed to anchor the jellyroll assembly to the flexible battery pouch by including an anchoring system configured to anchor the jellyroll assembly to the flexible battery pouch, which includes a plurality of anchors in the adhesive layer. The plurality of anchors is configured to create friction points against movement of the jellyroll assembly relative to the flexible pouch. This document now turns to example implementations of the battery pack having the adhesive layer with the plurality of anchors and the jellyroll assembly.

Example Implementations

The following discussion describes example implementations, techniques, and apparatuses that may be employed in the example implementations, and various devices in which components of the example implementations can be embodied. In the context of the present disclosure, reference is made to the following by way of example only.

FIG. 1illustrates an example implementation100of a set of layers102that may be included in a battery cell. The set of layers102includes a cathode layer104disposed as a top layer. Disposed beneath the cathode layer104is a separator layer106. Disposed beneath the separator layer106is an anode layer108. Disposed beneath the anode layer108is an insulator layer110. Although a specific ordering of the layers is illustrated inFIG. 1, the specific ordering is an example only. The ordering may be different, so long as the separator layer106is disposed between the cathode layer104and the anode layer108, and the insulator layer110is disposed adjacent to the cathode layer104or the anode layer108such that the insulator layer110and the separator layer106are on opposing sides of the cathode layer104or the anode layer108. In one example, the cathode layer104may be between the separator layer106and the insulator layer110. In another example, the anode layer108may be between the separator layer106and the insulator layer110.

FIG. 2illustrates an example implementation200of a battery cell configured as a jellyroll assembly202. As illustrated, the set of layers102, shown as a solid line, is wound into the jellyroll assembly202. Also illustrated is a magnified view204of a portion of the jellyroll assembly202, which shows the distinct layers of the set of layers102. The ordering of the layers in the example implementation200is a same ordering of the layers fromFIG. 1. Although a specific ordering of the layers is illustrated in the magnified view204ofFIG. 2, the specific ordering is an example only. The ordering may be different, so long as the cathode layer104and the anode layer108are separated by either the separator layer106or the insulator layer110to prevent an electrical short.

FIG. 3illustrates an example implementation300of a battery pack302. For the sake of clarity, some details, including interfaces and components, are omitted fromFIG. 3. As illustrated, the battery cell configured as the jellyroll assembly202fromFIG. 2is disposed within a flexible pouch304. A first electrically conductive tab306may physically connect to the cathode layer (e.g., the cathode layer104inFIG. 2) of the battery cell. A second electrically conductive tab308may physically connect to the anode layer (e.g., the anode layer108inFIG. 2) of the battery cell. Also illustrated are a first adhesive layer310and a second adhesive layer312. The first adhesive layer310may be referred to as “green tape” (green tape310). The second adhesive layer312may be referred to as “hot melt tape” (hot melt tape312).

The green tape310may be made from a polyethylene terephthalate (PET) material. The green tape310may include a first surface314configured to contact an outer surface of the battery cell and a second surface316opposite the first surface. The second surface316may include a plurality of anchors configured to create friction points against a movement (e.g., a slidable movement) of the jellyroll assembly202relative to the flexible pouch304. The plurality of anchors (e.g., described in relation toFIGS. 5-8) may be configured to reduce the movement of the jellyroll assembly202relative to the flexible pouch304by transferring or absorbing a momentum of the jellyroll assembly202within the flexible pouch304.

During assembly of the battery pack302, for example, the first surface of the green tape310may bond (e.g., adhesively) to the outer surface of the jellyroll assembly202. A first surface318of the hot melt tape312may be pasted on top of an overlap portion320of the second surface316of the green tape310and an overlap portion322of the outer surface of the jellyroll assembly202. The overlap portion320of the second surface316of the green tape310may be greater than one millimeter (mm), as an example. A second surface324opposite the first surface318of the hot melt tape312may adhere to the flexible pouch304. The hot melt tape312may bond (e.g., adhesively, chemically) to the green tape310, the jellyroll assembly202, and the flexible pouch304, which may be vacuum-sealed.

When subject to an exterior impact force (e.g., when dropped), for example, the hot melt tape312may reduce movement of the jellyroll assembly202relative to the flexible pouch304. Further, the green tape310may reduce a chance of tearing the outermost winding of the set of layers102of the jellyroll assembly202. Additionally, or optionally, the plurality of anchors of the green tape310may be configured to further reduce the movement of the jellyroll assembly202relative to the flexible pouch when subject to the exterior impact force.

FIG. 4illustrates a front view of an example implementation400of the battery pack302fromFIG. 3. As illustrated, the first electrically conductive tab306and the second electrically conductive tab308exit the flexible pouch304at one end (e.g., “top”) of the battery pack302. One of the two tabs connects to the cathode layer104, while the other connects to the anode layer108of the battery cell, some details of which are omitted fromFIG. 4for the sake of clarity. Also illustrated inFIG. 4are an outer surface402of the jellyroll assembly202, the second surface316of the green tape310, and the second surface324of the hot melt tape312. As examples, a width408of the green tape310not covered by the hot melt tape312may be in a range of nine mm to 15 mm and a width410of the overlap portion320of the green tape310by the hot melt tape312may be greater than one mm. As an additional example, a width412the hot melt tape312may be in a range of 19 mm to 21 mm.

As mentioned, the second surface316of the green tape310may include a plurality of anchors configured to create friction points against movement of the jellyroll assembly202relative to the flexible pouch304.FIGS. 5A and 5Billustrate an example implementation500of the green tape310-1having the plurality of anchors.FIG. 5Aillustrates a front view of the green tape310-1, the second surface316of which is shown. In this example, the plurality of anchors includes a pattern of bumps502(e.g., protrusions) extending from the second surface316of the green tape310-1.FIG. 5Bshows a cross-section view of the green tape310-1, taken along line A-A, which includes a bump502from the pattern of bumps502. Although a single pattern of bumps502of a single size is illustrated, the pattern and size of the bumps can be any pattern and size appropriate to create friction points against movement of the jellyroll assembly202relative to the flexible pouch304. As illustrated inFIG. 5and other FIGs. herein, the anchors (e.g., bumps502) are configured to reduce the movement of the jellyroll assembly relative to the flexible pouch by absorbing a portion of the translation component of the movement of the jellyroll assembly in the x-direction and/or the y-direction (e.g., in an xy-plane defined by the second surface316of the green tape310).

FIGS. 6A and 6Billustrate another example implementation600of the green tape310-2having the plurality of anchors.FIG. 6Aillustrates a front view of the green tape310-2, the second surface316of which is shown. In this example, the plurality of anchors includes a pattern of ripples602extending from the second surface316of the green tape310-2. The shaded portions (e.g., portions602-1) of the pattern of ripples602indicate concave portions (e.g., valleys) while the light portions (e.g., portions602-2) indicate convex portions (e.g., peaks).FIG. 6Bis a cross-section, taken along line B-B, of the green tape310-2including the pattern of ripples602. As illustrated, the second surface316of the green tape310-2includes the concave and convex portions of the pattern of ripples602. Although a single pattern of ripples602of a single size and orientation is illustrated, the pattern, size, and orientation of the ripples can be any pattern, size, and orientation appropriate to create friction points against movement of the jellyroll assembly202relative to the flexible pouch304.

FIGS. 7A and 7Billustrate another example implementation700of the green tape310-3having the plurality of anchors. In this example, illustrated by detail view700-1, the plurality of anchors includes a pattern of indentations702(e.g., recessed areas) in the second surface316of the green tape310-3.FIG. 7Bshows a cross-section view of the green tape310-3, taken along line C-C and illustrating an indentation702from the pattern of indentations702. Although a single pattern of indentations702of a single size is illustrated inFIG. 7A, the pattern and size of the indentations can be any pattern and size appropriate to create friction points against movement of the jellyroll assembly202relative to the flexible pouch304.

FIGS. 8A and 8Billustrate yet another example implementation800of the green tape310-4having the plurality of anchors.FIG. 8Aillustrates a front view of the green tape310-4, the second surface316of which is shown. In this example, the plurality of anchors includes a pattern of holes802in the green tape310-4. The pattern of holes802is further illustrated inFIG. 8B, a cross-section view of the green tape310taken along line D-D. Although a single pattern of holes802of a single size is illustrated, the pattern and size of the holes can be any pattern and size appropriate to create friction points against movement of the jellyroll assembly202relative to the flexible pouch304.

In implementations, the plurality of anchors can be any shape (e.g., pillar, cylinder, dome, spike, pinhole, channel, slot, recess), including, but not limited to, the bumps, ripples, indentations, and holes described in this discussion. The plurality of anchors can also be any size and orientation, so long as the plurality of anchors is configured to create friction points against movement of the jellyroll assembly202relative to the flexible pouch304. In some implementations, during assembly of the battery pack302, the plurality of anchors interlock with the flexible pouch based on a vacuum seal. Additionally, or optionally, the plurality of anchors interlock with the flexible pouch304based on a curing of the green tape310and the flexible pouch304. In some implementations, the plurality of anchors may interlock with the hot melt tape312in the overlap portion320of the green tape310by the hot melt tape312.

Although concepts of techniques and apparatuses directed to a battery-cell-to-battery-pouch anchoring system have been described in language specific to techniques and/or apparatuses, it is to be understood that the subject of the appended claims is not necessarily limited to the specific techniques or apparatuses described. Rather, the specific techniques and apparatuses are disclosed as example implementations of a battery-cell-to-battery-pouch anchoring system.