WO2024040161A1

WO2024040161A1 - An enclosure

Info

Publication number: WO2024040161A1
Application number: PCT/US2023/072373
Authority: WO
Inventors: Mark Andrew ELLIS; Hanna WIGGMAN; Oskar LUND; Love FÄLTSTRÖM; Vijay Kumar; Diego Buriti ARAUJO
Original assignee: Cuberg, Inc.
Priority date: 2022-08-17
Filing date: 2023-08-17
Publication date: 2024-02-22
Also published as: SE2250972A1

Abstract

An enclosure for a plurality of pouch battery cells, the enclosure comprising a plurality of receptacles, each receptacle configured to receive a respective one of the plurality of pouch battery cells and wherein each receptacle includes a normally-closed cover, the cover configured to adopt an open configuration to reveal an aperture in the receptacle to allow material ejected from the pouch battery cell that is mounted in the receptacle to leave the receptacle and, in its normally-closed configuration, at least partially close the aperture to prevent material ejected from a different one of the receptacles from entering the receptacle.

Description

PCT Application

AN ENCLOSURE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Swedish Patent Application No. 2250972-3, filed on 2022-08-17, which is incorporated herein by reference in its entirety for all purposes.

FIELD

[0002] The present disclosure relates to an enclosure for a plurality of pouch battery cells. It also relates to a tray for stacking with other trays to form the enclosure. The disclosure also relates to a battery module.

BACKGROUND

[0003] Pouch battery cells comprise an electrochemical cell housed within a pouch. The safety of pouch battery cells is important. The electrochemical cell within the pouch may experience thermal runaway, in which there is uncontrolled self-heating. Thermal runaway may be caused by damage to the pouch battery cell or, in particular, the electrochemical cell housed therein. Pressure may build within the pouch during such a thermal runaway event, which may lead to the rupture of the pouch and the violent ejection of material. A plurality of pouch battery cells may be mounted together and thus the ejection of material from one of the pouch battery cells presents a hazard.

SUMMARY

[0004] According to a first aspect of the present disclosure, there is provided an enclosure for a plurality of pouch battery cells, the enclosure comprising a plurality of receptacles, each receptacle configured to receive a respective one of the plurality of pouch battery cells and wherein each receptacle includes a normally-closed cover, the cover configured to adopt an open configuration to reveal an aperture in the receptacle to allow material ejected from the pouch battery cell that is mounted in the receptacle to leave the receptacle and, in its normally-closed configuration, at least partially close the aperture to prevent material ejected from a different one of the receptacles from entering the receptacle.

[0005] In one or more embodiments, the enclosure includes a common channel that extends, longitudinally, alongside each of the plurality of receptacles and wherein two or more of the apertures of each of the plurality of receptacles are configured to open into the common channel when the covers are in the open configuration.

[0006] In one or more embodiments, one or more of the apertures include an outlet portion configured to open into the common channel, wherein the outlet portion includes a guide member configured to direct the material leaving therethrough in a longitudinal direction of the channel.

[0007] In one or more embodiments, the normally closed cover comprises any one of: a one-way valve; a localized weakened portion of the receptacle; a rupturable sheet over the aperture; a flap configured to close the aperture; and a flap configured to at least partially close the aperture.

[0008] In one or more embodiments, one or more of the covers comprise a flap, wherein the aperture and the flap are formed in a wall of each of the receptacles and wherein each flap is configured such that a free end of the flap is biased such that it prevents material ejected from a different one of the receptacles from entering the receptacle in the normally-closed configuration.

[0009] In one or more embodiments, the flap is one of: biased to abut an outside surface of the wall of which it is part; or biased to abut an outside surface of a wall of an adjacent receptacle.

[0010] In one or more embodiments, the flap, in its open position, comprises said guide member.

[0011] In one or more embodiments, the enclosure is formed of a plurality of trays, each tray comprising a surface and a plurality of side walls extending from the outer edges of the surface; wherein the plurality of trays are configured to stack together and wherein each of the receptacles for receiving the pouch battery cells is defined by spaces between pairs of stacked trays; and wherein one of the plurality of side walls of each tray comprises said wall in which the aperture and the flap are formed; and wherein the flap of each tray is configured such that the free end of the flap is biased to close the aperture of a directly adjacent tray that is stacked within it.

[0012] In one or more embodiments, the tray comprises a laminated material having a plurality of layers and wherein the flap of each tray is formed by a region having fewer layers than a neighboring portion of the tray such that the flap has increased flexibility.

[0013] In one or more embodiments, the tray is comprised of carbon fibre layers.

[0014] According to a first aspect of the present disclosure, there is provided a battery module comprising: an enclosure according to the first aspect; a plurality of pouch battery cells; wherein each receptacle of the enclosure houses one or more of the plurality of pouch battery cells.

[0015] While the disclosure is amenable to various modifications and alternative forms, specifics thereof have been shown by way of examples in the drawings and will be described in detail.

[0016] The Figures and the Detailed Description that follow also exemplify various example embodiments. Various example embodiments may be more completely understood in consideration of the following Detailed Description in connection with the accompanying Drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] One or more embodiments will now be described by way of example only with reference to the accompanying drawings in which:

[0018] Figure 1 shows an example pouch battery cell;

[0019] Figure 2 shows an example embodiment of an enclosure;

[0020] Figure 3 shows an example guide portion; and

[0021] Figure 4 shows an example embodiment formed of trays stacked together to form part of an enclosure.

DETAILED DESCRIPTION

[0022] Example Figure 1 shows a pouch battery cell 100. The pouch battery cell 100 comprises an electrochemical cell and a pouch 101 configured to house the electrochemical cell. It will be appreciated that the electrochemical cell is hidden from view in Figure 1 due to being housed in the pouch 101 but is located within a section 102.

[0023] The electrochemical cell may comprise a secondary cell, although the electrochemical cell may be a primary cell or other cell type. As will be familiar to those skilled in the art, the electrochemical cell may comprise an assembly of electrodes and the electrolyte for producing and storing electrical energy. In a pouch battery cell, the electrodes and the electrolyte are typically formed in a series of layers. It will however be appreciated that the form of the electrochemical cell is not the focus in this document. The pouch 101 may be configured to provide an outermost layer to contain the electrodes and the electrolyte therein.

[0024] The pouch 101 may be formed of two layers (although further sub-layers may or may not be present) that are sealed together at their peripheral edge to form a peripheral flange 103. The sealing of the layers of the pouch 101 thereby seals the electrochemical cell within the pouch 101. It will be appreciated that the pouch may comprise a non-structural housing and may be of a relatively flexible material, such as a film.

[0025] The pouch battery cell 100 includes at least a first connector arrangement 104 configured to extend through the peripheral flange 103 and provide for electrical connection to the electrochemical cell housed within the pouch 101. Generally, the connector arrangement comprises a positive connector terminal and a negative connector terminal.

[0026] It will be appreciated that defects in the electrochemical cell, such as caused by damage or by other reasons, may lead to an increase in heat and pressure within the electrochemical cell that builds up within the pouch 101. As will be known in the art, the pouch battery cell 100 may experience "thermal runaway" in which chemical reactions within the pouch battery cell create temperatures and pressures within the pouch 101 beyond its design limits which will lead to rupture of the pouch 101. The layers of the pouch 101 at the peripheral flange 103 may be forced apart and material from the electrochemical cell may be ejected.

[0027] A plurality of pouch battery cells 100 may be arranged together and mounted within an enclosure. It is important in one or more embodiments, that the enclosure can manage the ejection of materials from a pouch battery cell mounted within it. In one or more embodiments the enclosure may be configured to prevent the material ejected from one pouch battery cell affecting a nearby pouch battery cell. The ejected material may affect a nearby cell for one or more reasons such as by virtue of it being conductive, its temperature, the speed of ejection or the direction of ejection.

[0028] Figure 2 shows an example of enclosure 200 for a plurality of pouch battery cells 100. The enclosure 200 comprises a plurality of receptacles 201, 202, 203, and 204. Each receptacle is configured to receive a respective one of the plurality of pouch battery cells 100. In other examples, one or more of each of the receptacles 201-204 may be configured to receive more than one of the pouch battery cells 100. Although four receptacles are shown in the example Figure 2, the enclosure 200 may comprise more or less than four receptacles 201-204. Each receptacle 201-204 includes a normally-closed cover 205, 206, 207, 208 over an aperture 210. In one or more examples, there may be one or more receptacles in the enclosure 200 that do not have covers. The covers 205-208 are configured and arranged such that they move to an open configuration to allow material ejected from the pouch battery cell 100 that is mounted in the receptacle 201-204 to leave that receptacle 201-204 via the aperture 210. Thus, the covers 205-208 may be configured to at least move to an open configuration or position to allow material to leave the receptacle 201-204. However, as the release of material from the pouch battery cell 100 occurs during extreme conditions, such as thermal runaway, after moving to the open configuration the cover 205-208 may or may not return to the normally-closed position.

[0029] The cover 205 (for example, but it could be any of the covers 205-208) is configured, in its normally-closed configuration, to prevent material ejected from a different one of the receptacles (202-204 in this example) from entering the receptacle 201 of which the cover 205 forms part.

[0030] Thus, the normally-closed cover 205-208 is configured to prevent ingress of material into the receptacle of which it is part by virtue of its normally closed position. Further the cover is configured, in this example, such that it opens in a direction (shown by arrow 214) that allows for egress of material from the receptacle 201-204. The covers may be configured to move to or adopt the open configuration only when a threshold force or pressure is applied to them from within the respective receptacle 201-204. The threshold force or pressure may be based on the force or pressure experienced during a thermal runaway event. [0031] In the example of Figure 2, the normally closed covers 205-208 are shown as a hinged or resilient flap 211 at least partially covering the aperture 210 in the receptable 201-204, through which the material ejected from the pouch battery cell loaded in the respective receptacle 201-204 can leave. The aperture 210 and flap 211 are formed in a wall of each or at least one or more of the receptacles 201-204. The flap 211 may be configured to be moved to its open position by the force of the material leaving the pouch battery cell 100 that is within the receptacle 201. Thus, the resilience of the flap 211 and/or hinge may be such that under normal conditions it remains in the normally closed position at least partially closing the aperture 210 but under conditions in which failure of the pouch battery cell within the receptacle occurs that leads to material ejection, then it is sufficiently flexible to open. In other examples, the hinge between the flap 211 and the wall of the receptacle is configured to operate in a similar way.

[0032] In other examples, the flap 211 is biased to the closed position by a biasing member, such as a spring. Thus, the flap 211 closes the aperture 210 and is configured to hold its closed configuration by way of the force of the spring, under normal operating conditions.

[0033] The flap 211 may be configured to prevent material from entering the receptacle 201-204 from the region 209. As shown, the region 209 comprises a region that may receive material ejected from other pouch battery cells 100 loaded in other ones of the receptacles 201-204.

[0034] The hinged or resilient flap 211 may be biased to the closed position such as against a wall 213 of the receptacle. In the example of Figure 2, a free end 212 of the flap 211 is located to abut or to lie close to (i.e. within a predetermined distance of) a wall 213 of the receptacle which may be adjacent to the aperture 210. By abutting an outer surface of the wall 213, the flap 211 is prevented from opening inwards, into the receptacle 201-204, thereby protecting the pouch battery cell mounted within it from being damaged by material ejected from a neighbouring or, more generally, a different one of the receptacles 201-204.

[0035] Thus, generally, in one or more examples, the flap 211 and aperture 210 may have one or more of the following features. The flap 211 may be biased to close the aperture 210, such as by a spring or by the resilience of the material of which it is made. The flap 211 may be configured and/or arranged to prevent it opening inwards under the force of material ejected from a different one of the receptacles or at all. As an example, the flap 211 may be biased to abut an outside surface of the wall 213 of the receptacle of which it is part. The flap 211 may be configured to open, such as in an outwards direction 214, only above a threshold opening force, which may be based on the typical force of ejection of material of a pouch battery cell 100 mounted within the receptacle of which the flap 211 forms part. Thus, there may be a separate structure to manage the venting of gas.

[0036] In the example of Figure 2, the enclosure includes a common channel that extends, longitudinally, alongside each of the plurality of receptacles. The channel is defined between the receptacles 201-204 and a channel wall 215 wherein the region 209 comprises the interior of the channel. In the present example, all of the covers 205-208 of each of the plurality of receptacles 201-204 are configured to open into the common channel or region 209. However, in other examples, two or more of the covers open into the common channel. In other embodiments, however, a majority of the covers open into the common channel. However, in other examples, a first subset of the receptacles may have covers on one side and a second subset of the receptacles may have covers on a different side, and therefore the respective subsets may open into respective common channels (not shown in the figures).

[0037] When the apertures 210 of the receptacles 201-204 open into a common channel or region 209 there is a risk that material ejected from one of the receptacles 201-204 may rebound from the channel wall 215 and impact a different one of the channels. The material ejected that rebounds could cause further damage, which is undesirable. Thus, the covers 205-208 may be advantageous in that they provide protection against ejected material rebounding and entering a neighboring one of the receptacles 201-204.

[0038] The risk of rebounding ejected material may be further decreased by a guide portion. Example Figure 3 shows a close-up of the cover 205 of receptacle 201 wherein flap 211 is in the open position. The guide portion 300, in this example, is formed by the flap 211, which is configured to open to an acute angle. In other examples, a further member in addition to the flap 211 or other embodiment of the cover is located at an exit of the aperture 210 and is arranged at an acute angle. Thus, in general, one or more of the covers 205-208 may include an outlet portion configured to open into the common channel or region 209, wherein the outlet portion includes a guide member 211 configured to direct the material leaving therethrough in a longitudinal direction 216 of the channel.

[0039] The guide portion 211 may act to redirect the flow of material that leaves the receptacle by the apertures. The redirection may be to a direction that reduces the chance of material rebounding from a surface that faces the aperture 210, that is channel wall 215, back towards the receptacle 201 or a neighboring receptacle 202- 204.

[0040] Figure 4 shows a second embodiment in which the enclosure 400 is formed of a plurality of trays 401-404. Figure 4 shows tray 401 separate from the others in an upper half and then stacked together with the other trays in the lower half. Each tray 401 comprises a surface 405, which forms the base or major surface of the tray 401. Each tray includes a plurality of raised side walls 406 extending from the outer edges of the surface 405. It will be appreciated that Figure 4 shows an end of the tray and the full tray may include two, three, or four side walls.

[0041] As shown in Figure 4, the plurality of trays 405 are configured to stack together and wherein each of the receptacles 411, 412, 413, and 414 for receiving the pouch battery cells 100 are defined by spaces between pairs of stacked trays. Thus, receptacle 411 is formed between tray 401 and tray 402. Likewise, receptacle 412 is formed between tray 402 and tray 403. Likewise, receptacle 413 is formed between tray 403 and tray 404. A final tray in the stack that forms the enclosure 400 may be closed by a tray or an end cap (not shown) to define the final receptacle in the stack.

[0042] In this embodiment, one of the plurality of side walls of each tray 401-404 includes the aperture 407 and the flap 408. Thus, the aperture 407 is formed by a slot in the side wall 406 and the flap 408 extends from a free end of the side wall 406.

[0043] The flap of each tray is configured such that the free end of the flap is biased to close the aperture of a directly adjacent tray that is stacked within it. Thus, the flap 408 of the (first) tray 401 is configured to close the aperture 415 that is formed in the wall of the (second) tray 402 and so on.

[0044] In the example of Figure 4, the flap 408 is biased to abut an outside surface of a wall of an adjacent receptacle, that is an adjacent tray wall. Thus, the flap 408 is prevented from opening inwards into the receptacle 412 and thereby may act as a oneway valve for receptacle 412. However, as in the previous embodiment, the flaps 408 may be configured to open under a threshold force of material ejected from inside the receptacle. Flap 420 of tray 403 is shown in the open position and arrow 421 illustrates material ejected from a pouch battery cell 422 leaving by the aperture of tray 404 and being guided by the flap 420 in the longitudinal direction of the channel defined by wall 417.

[0045] Also shown in Figure 4 are legs 416 which extend from the trays 401-405 (or a different structure in other embodiments) to support the channel wall 417. Further, each receptacle 411-414 may include a cell spacer 423 and one or more flange supports 424.

[0046] Figure 4 also shows the tray 401 including a cover comprising a sacrificial panel 430 covering its aperture 407. The sacrificial panel may comprise a sheet configured to rupture to reveal the aperture 407. The sacrificial panel may be configured to burst open at a threshold force experienced when the material is ejected from the pouch battery cell within the receptacle 411. However, it may have sufficient resilience to resist material that rebounds from channel wall 417 from a neighboring receptacle. The sacrificial panel may be required for one of the trays because the first tray 401 is not stacked within a further tray and therefore does not receive a flap to cover its aperture. Structures other than a sacrificial panel may be provided.

[0047] In general, the normally closed cover comprises any one of: a one-way valve; a localized weakened portion of the receptacle; a rupturable sheet over the aperture; a flap configured to close the aperture; and a flap configured to at least partially close the aperture.

[0048] Each tray 410-404 or receptacle 201-204 may comprise a laminated material having a plurality of layers, such as a carbon fibre laminate. The flaps 211, 408 of each tray or receptacle may be formed by a region having fewer layers than a neighboring portion or remainder of the tray 401-404 or receptacle 201-204 such that the flap has increased flexibility. Thus, the flap is able to bend to perform its function as a one-way valve.

[0049] In other examples, the tray 410-404 or receptacle 201-204 may comprise a non-laminated material. In other examples, the flaps 211, 408 may be formed by a weakened section of the receptacle 201-204 or tray 410-404 to act as a hinge. [0050] It will be appreciated that the trays 401-404 may form an aspect of this disclosure. A tray is used for forming an enclosure by stacking together with one or more other trays such that receptacles for receiving pouch battery cells are defined by spaces between pairs of stacked trays. The tray comprises a surface and one or more side walls. One of the one or more side walls defines an aperture and a flap. The flap of each tray is configured such that, when in use, the free end of the flap is biased to close the aperture of a directly adjacent tray that is stacked within it.

[0051] In one or more examples described above the cover is shown as a flap 211 covering an aperture. However, the cover of each receptacle 201-204 may comprise a one-way valve which may comprise one of a reed valve, a diaphragm valve, a swing check valve, and a duckbill check valve. It will also be appreciated that in any of the embodiments, different covers or valve types may be present in the same enclosure. In any of the example embodiments, there may be receptacles that do not include the covers.

[0052] It will be appreciated that, with reference to Figure 2 and Figure 4, when the enclosure 200 or the enclosure 400 is loaded with pouch battery cells 100 it may form a battery module. Thus, the battery module may comprise an enclosure as described in any of the examples above and a plurality of pouch battery cells 100, wherein each receptacle 201-204, 411-414 of the enclosure houses one or more of the plurality of pouch battery cells 100. In one or more examples, the pouch battery cells 100 are electrically coupled together or in groups.

Claims

1. An enclosure for a plurality of pouch battery cells, the enclosure comprising: a plurality of receptacles, each receptacle configured to receive a respective one of the plurality of pouch battery cells, wherein each receptacle includes a normally-closed cover, wherein the cover is configured to adopt an open configuration to reveal an aperture in the receptacle to allow material ejected from the pouch battery cell that is mounted in the receptacle to leave the receptacle and, in its normally-closed configuration, at least partially close the aperture to prevent material ejected from a different one of the receptacles from entering the receptacle.

2. The enclosure of claim 1, wherein the enclosure includes a common channel that extends, longitudinally, alongside each of the plurality of receptacles and wherein two or more of the apertures of each of the plurality of receptacles are configured to open into the common channel, when the covers are in the open configuration.

3. The enclosure of claim 2, wherein one or more of the apertures include an outlet portion configured to open into the common channel, wherein the outlet portion includes a guide member configured to direct the material leaving therethrough in a longitudinal direction of the channel.

4. The enclosure of claim 1, wherein the normally closed cover comprises any one of: a one-way valve; a localised weakened portion of the receptacle; a rupturable sheet over the aperture; a flap configured to close the aperture; and a flap configured to at least partially close the aperture.

5. The enclosure of claim 1, wherein one or more of the covers comprise a flap, wherein the aperture and the flap are formed in a wall of each of the receptacles, and wherein each flap is configured such that a free end of the flap is biased such that it prevents material ejected from a different one of the receptacles from entering the receptacle in the normally-closed configuration.

6. The enclosure of claim 5, wherein the flap is one of: biased to abut an outside surface of the wall of which it is part; or biased to abut an outside surface of a wall of an adjacent receptacle.

7. The enclosure of claim 5 when dependent on claim 3, wherein the flap, in its open position, comprises said guide member.

8. The enclosure of claim 5, wherein the enclosure is formed of a plurality of trays, each tray comprising a surface and a plurality of side walls extending from outer edges of the surface, wherein the plurality of trays are configured to stack together and wherein each of the receptacles for receiving the pouch battery cells are defined by spaces between pairs of stacked trays, wherein one of the plurality of side walls of each tray comprises said wall in which the aperture and the flap are formed, and wherein the flap of each tray is configured such that the free end of the flap is biased to close the aperture of a directly adjacent tray that is stacked within it.

9. The enclosure of claim 8, wherein the tray comprises a laminated material having a plurality of layers and wherein the flap of each tray is formed by a region having fewer layers than a neighbouring portion of the tray such that the flap has increased flexibility.

10. The enclosure of claim 9, wherein the tray is comprised of carbon fibre layers.

11. A battery module comprising: an enclosure according to any preceding claim; and a plurality of pouch battery cells, wherein each receptacle of the enclosure houses one or more of the plurality of pouch battery cells.