TECHNICAL FIELD

The present disclosure generally pertains to a drying chamber assembly for drying battery electrodes, a method for reducing ramp-up time in such a drying chamber assembly, a method for operating such a drying chamber assembly, a method for drying battery electrodes, a method for retrofitting a drying chamber assembly, a computer program and a use of a by-pass duct in a drying chamber assembly.

BACKGROUND

In addressing climate change, there is an increasing demand for rechargeable batteries, e.g. to enable electrification of transportation and to supplement renewable energy.

The electrodes of such batteries generally comprise an electrically conductive sheet (also referred to as “foil”) coated with an anode or cathode material. The coating is generally applied as a slurry comprising a solvent and the electrode material, after which the electrode is dried in a drying chamber to evaporate the solvent. Usually, the drying is accomplished by subjecting the electrode to hot air in the drying chamber. In the case of an interruption in the operation of the drying chamber, e.g. an electrode foil break or for maintenance of the drying chamber, the drying chamber has to be stopped and the flow of hot air has to be interrupted to allow the restore a continuous foil path.

As the demand for rechargeable batteries increases, more and more focus is being placed on production speed. To achieve an effective production of rechargeable batteries, each step in the production can be optimized. SUMMARY

It is in view of the above considerations and others that the embodiments of the present invention have been made. The present disclosure aims at providing a drying chamber assembly that allows the efficient manufacture of electrodes even in the event of an electrode foil break or maintenance of the drying chamber.

According to a first aspect, the present disclosure provides a drying chamber assembly for drying battery electrodes, comprising a drying chamber having an entry port for an electrode foil and an exit port for the electrode foil, a solvent collector, a heater, an exhaust duct configured to lead fluid from the drying chamber to the solvent collector, a supply duct configured to lead fluid from the solvent collector to the heater, an inlet duct configured to lead fluid to the drying chamber from the heater, and a first by-pass duct configured to lead fluid from the inlet duct to the exhaust duct, and a first valve assembly configured to control the flow of fluid from the heater to the drying chamber and to the exhaust duct, the first valve assembly being able to redirect the flow of fluid from the heater to the exhaust duct, thereby by-passing the drying chamber.

Specifically, the fluid may be air. In such a case, the fluid leaving the drying chamber is a mixture of air and evaporated solvent.

The first valve assembly may comprise one or two valves.

The first valve assembly may comprise any kind of valves that can regulated the flow of the fluid. One example of a suitable valve is a damper.

In case of an interruption in the function of the drying chamber, the fluid can be recirculated from the heater to the inlet duct, through the first by-pass duct to the exhaust duct and further through the solvent collector and the supply duct back to the heater. This has the advantage that the temperature of the fluid as well as the temperature of the ducts are kept at essentially the temperature(s) needed during operation of the drying chamber assembly. Thus, the time period from start of the flow of fluid into the drying chamber after an interruption to the time point where an electrode can be dried (referred to as the ramp-up time) is reduced compared to the time period needed in an conventional drying chamber assembly. Typically, the time needed to reheat the drying chamber assembly is reduced to less than one hour, specifically to 20 to 30 minutes. In conventional drying chamber assemblies, when the operation of the drying chamber is interrupted, the flow of fluid is also stopped. Thus, the temperature of the fluid as well as the temperature of the ducts are allowed to decrease. When the drying chamber is ready to be used again, time is needed to allow for the ducts to reach the correct temperatures, in order to deliver a fluid of the correct temperature the the drying chamber and thereby allow the correct function of the drying chamber assembly. Typically, the time needed to reheat a conventional drying chamber assembly is 1 to 2 hours.

According to one embodiment, the drying chamber assembly further comprises a second valve assembly configured to control the flow of fluid from the first by-pass duct to the exhaust duct and being able to allow flow of fluid from the heater to the exhaust duct.

The second valve assembly may comprise one or two valves.

The second valve assembly may comprise any kind of valves that can regulated the flow of the fluid. One example of a suitable valve is a damper.

Thus, according to one embodiment, the first valve assembly comprises one or two valves and/or the second valve assembly comprises one or two valves.

According to another embodiment, the first by-pass duct is connected to the inlet duct at a position located at a distance DI from the drying chamber, wherein the distance DI is less than 20 % of the length of the inlet duct, and/or the first by-pass duct is connected to the exhaust duct at a position located at a distance D2 from the drying chamber, wherein the distance D2 is less than 20 % of the length of the exhaust duct.

Specifically, the distance DI is less than 15 %, such as less than 10 %, such as less than 5 % such as less than 3 % of the total length of the inlet duct.

Specifically, the distance D2 is less than 15 %, such as less than 10 %, such as less than 5 %, such as less than 3 % of the total length of the exhaust duct.

Advantageously, the distance DI and/or the distance D2 is as short as possible, since this will prevent cooling of the ducts during interruption of operation of the drying chamber. This will lead to a shorter ramp-up time when the drying chamber is put into operation. According to one embodiment, the drying chamber assembly further comprises a second bypass duct configured to lead fluid from the exhaust duct to the supply duct, and a third valve assembly configured to control the flow of fluid from the exhaust duct to the solvent collector and to the supply duct, the third valve assembly being able to redirect the flow of fluid from the exhaust duct to the supply duct, thereby by-passing the solvent collector.

Through the second by-pass duct, the solvent collector can be by-passed.

The third valve assembly may comprise one or two valves.

The third valve assembly may comprise any kind of valves that can regulated the flow of the fluid. One example of a suitable valve is a damper.

According to another embodiment, the drying chamber assembly may further comprise a fourth valve assembly configured to control the flow of fluid from the second by-pass duct to the supply duct and being able to allow flow of fluid from the exhaust duct to the supply duct.

The fourth valve assembly may comprise one or two valves.

The fourth valve assembly may comprise any kind of valves that can regulated the flow of the fluid. One example of a suitable valve is a damper.

Thus, according to one embodiment, the third valve assembly comprises one or two valves and/or the fourth valve assembly comprises one or two valves.

According to another embodiment, the second by-pass duct is connected to the exhaust duct at a position located at a distance D3 from the solvent collector, wherein the distance D3 is less than 20 % of the length of the exhaust duct, and/or the second by-pass duct is connected to the supply duct at a position located at a distance D4 from the solvent collector, wherein the distance D4 is less than 20 % of the length of the supply duct.

Specifically, the distance D3 is less than 15 %, such as less than 10 %, such as less than 5 %, such as less than 3 % of the total length of the exhaust duct.

Specifically, the distance D4 is less than 15 %, such as less than 10 %, such as less than 5 %, such as less than 3 % of the total length of the supply duct. Advantageously, the distance D3 and/or the distance D4 is as short as possible, since this will prevent cooling of the ducts during interruption of operation of the drying chamber. This will lead to a shorter ramp-up time when the drying chamber is put into operation.

According to another aspect, the present disclosure provides a method for reducing ramp-up time in a drying chamber assembly according to the present disclosure, wherein the method comprises bypassing the drying chamber by redirecting the flow of fluid from the heater to the exhaust duct.

According to one embodiment, the method further comprises bypassing the solvent collector by redirecting the flow of fluid from the exhaust duct to the supply duct.

According to a further aspect, the present disclosure provides a method for drying battery electrodes with hot fluid in a drying chamber, wherein the drying chamber is configured to dry a coated electrode foil entering the drying chamber at an entry port and exiting the drying chamber at an exit port; wherein the method comprises the steps of feeding hot fluid to the drying chamber from a heater via an inlet duct, leading at least a portion of the flow of fluid from the drying chamber to a solvent collector via an exhaust duct, and leading fluid from the solvent collector to the heater via a supply duct; wherein, in the event of an interruption of the operation of the drying chamber, the method comprises the step of bypassing the drying chamber by redirecting the flow of fluid from the heater to the exhaust duct via a first by-pass duct.

The interruption of the operation of the drying chamber may for example be due to a foil break. Other reasons for interruption of the operation of the drying chamber may be maintenance of the drying chamber or that a part of the drying chamber has to replaced or mended.

According to one embodiment, in the event of an interruption of the operation of the drying chamber, the method further comprises bypassing the solvent collector by redirecting the flow of fluid from the exhaust duct to the supply duct via a second by-pass duct.

According to a further aspect, the present disclosure provides a method for retrofitting a drying chamber assembly for drying battery electrodes, wherein the drying chamber assembly comprises a drying chamber having an entry port for an electrode foil and an exit port for the electrode foil, a solvent collector, a heater, an exhaust duct configured to lead fluid from the drying chamber to the solvent collector, a supply duct configured to lead fluid from the solvent collector to the heater, and an inlet duct configured to lead fluid to the drying chamber from the heater; wherein the method comprises installing a first by-pass duct configured to lead fluid from the from the inlet duct to the exhaust duct, and a first valve assembly configured to control the flow of fluid from the heater to the drying chamber and to the exhaust duct, the first valve assembly being able to redirect the flow of fluid from the heater to the exhaust duct via the first by-pass duct, thereby by-passing the drying chamber.

The method for retrofitting a drying chamber assembly for drying battery electrodes may further comprise installing a second valve assembly configured to control the flow of fluid from the first by-pass duct to the exhaust duct and being able to allow flow of fluid from the heater to the exhaust duct.

According to one embodiment, the method for retrofitting a drying chamber assembly for drying battery electrodes further comprises installing a second by-pass duct configured to lead fluid from the exhaust duct to the supply duct, and a third valve assembly configured to control the flow of fluid from the exhaust duct to the solvent collector and to the supply duct, the third valve assembly being able to redirect the flow of fluid from the exhaust duct to the supply duct via the second by-pass duct, thereby by-passing the solvent collector.

The method for retrofitting a drying chamber assembly for drying battery electrodes may, in addition to installing the third valve assembly, further comprise installing a fourth valve assembly configured to control the flow of fluid from the second by-pass duct to the supply duct and being able to allow flow of fluid from the exhaust duct to the supply duct.

According to a further aspect, the present disclosure provides a method of operating a drying chamber assembly for drying battery electrodes, wherein the method comprises sensing if an electrode foil break has occurred in the drying chamber, and in the event of an electrofde foil break: by-passing the drying chamber by redirecting the flow of fluid from the heater to the exhaust duct. This may be accomplished by regulating a first valve assembly and, optionally a second valve assembly.

According to one embodiment, the method of operating a drying chamber assembly according to the present disclosure further comprises by-passing the solvent collector by redirecting the flow of fluid from the exhaust duct to the supply duct. This may be accomplished by regulating a third valve assembly and, optionally a fourth valve assembly. According to a further aspect, the present disclosure provides a computer program comprising instructions to cause the first valve assembly and, optionally, the third valve assembly to execute the steps of the method of operating a drying chamber assembly for drying battery electrodes according to the present disclosure.

The computer program may further comprise instructions to cause the second valve assembly and/or the fourth valve assembly to execute the steps of the method of operating a drying chamber assembly for drying battery electrodes according to the present disclosure.

According to a further aspect, the present disclosure provides a use of a by-pass duct in a drying chamber assembly for drying battery electrodes, wherein the by-pass duct is used to by-pass a drying chamber in the event of an interruption of the operation of the drying chamber.

The interruption of the operation of the drying chamber may for example be due to a foil break. Other reasons for interruption of the operation of the drying chamber may be maintenance of the drying chamber or that a part of the drying chamber has to replaced or mended.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments disclosed herein are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings. Like reference numerals refer to corresponding parts throughout the drawings, in which

Figure 1 schematically illustrates a conventional drying chamber assembly,

Figure 2a shows a first embodiment of a drying chamber assembly according to the present disclosure,

Figure 2b shows a second embodiment of a drying chamber assembly according to the present disclosure,

Figure 3a shows a third embodiment of a drying chamber assembly according to the present disclosure,

Figure 3b shows a fourth embodiment of a drying chamber assembly according to the present disclosure, Figure 4a illustrates the pathway for the fluid during operation of a drying chamber assembly according to the present disclosure,

Figure 4b illustrates the pathway for the fluid during interruption of the operation of drying chamber of a drying chamber assembly according to the present disclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure will now be described more fully hereinafter. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those persons skilled in the art.

In short, electrodes for batteries can be produced by coating a metal foil with a slurry comprising solvent, binder, and electrode material such as e.g. graphite and silicon. For cathodes, the solvent typically is N-methyl-2-pyrrolidone (nMP) and for anodes the solvent typically is water. The slurry is dried in a drying chamber where the coated electrode is heated with a hot fluid, usually hot air. The fluid may herein also be referred to as drying fluid. The dried coated electrodes are thereafter further processed into electrodes for batteries. The evaporated solvent leaves the drying chamber and is separated from the drying fluid in a solvent collector. The solvent can be used again to prepare a coating slurry. The drying fluid is heated in a heater and recycled to the drying chamber. The length of the drying chamber may vary between 2 m to 50 m, typically between 35 and 50 m.

During production of electrodes, interruptions in the operation of the drying chamber may occur. The interruption of the operation of the drying chamber may for example be due to an electrode foil break. Other reasons for interruption of the operation of the drying chamber may be maintenance of the drying chamber or that a part of the drying chamber has to replaced or mended. In such cases, the flow of hot fluid through the drying chamber must be interrupted in order to allow a restoration of the electrode foil path, maintenance of the drying chamber or mending of broken parts. In the case of an electrode foil break, it may take as long as 3 to 5 hours until the drying chamber is operational again. Typically, it takes 30 minutes to 1 hour for the drying chamber to cool down, about 2 hours to fix the electrode foil break and 1 to 2 hours to reheat the drying chamber assembly.

In the figures, the arrow indicates the direction of the electrode foil through the drying chamber.

Drying chamber assembly

Figure 1 schematically illustrates a conventional drying chamber assembly 10a. An electrode foil F coated with a slurry comprising a solvent, binders and electrode material, enters the drying chamber 1 at entry port A. In the drying chamber 1, the electrode foil F is dried by hot fluid, usually hot air, entering the drying chamber via the inlet duct 6. Dried electrode foil F exits the drying chamber 1 at exit port B. The drying fluid, comprising evaporated solvent from the slurry, exits the drying chamber 1 through exhaust duct 4 and is fed to the solvent collector 2. In the solvent collector 2, the solvent is separated from the drying fluid and exits the solvent collector 2 through the solvent outlet C. The solvent may be recycled and reused for preparing new slurry. From the solvent collector 2 the drying fluid is fed through the supply duct 5 to the heater 3, where the drying fluid is heated and again fed through the inlet duct 6 to the drying chamber 1.

During production of electrodes, interruptions in the operation of the drying chamber 1 may occur. The interruption of the operation of the drying chamber may for example be an electrode foil break. Other reasons for interruption of the operation of the drying chamber 1 may be maintenance of the drying chamber 1 or that a part of the drying chamber has to replaced or mended. In such cases, the flow of hot fluid through the drying chamber 1 must be interrupted in order to allow a restoration of the foil path, maintenance or mending of broken parts. As the flow of drying fluid is stopped, the fluid as well as the inlet duct 6, the exhaust duct 4 and the supply duct 5 cool down. When the drying chamber 1 is operational and ready to use again, the flow of drying fluid is started and heated in the heater 3. However, since the inlet duct 6, the exhaust duct 4 and the supply duct 5 have cooled down there is a ramp-up time before the drying chamber assembly 10a is fully operational and can be used to dry electrodes.

Figures 2a, 2b, 3a and 3b illustrate different embodiment of the present disclosure and include the general structures shown in Figure 2a. The drying chamber assembly 10b for drying battery electrodes according to the present disclosure is especially advantageous in cases where the drying chamber 1 is more then 25 m, such as more than 30 m, such as more than 40 m, such as more than 50 m long.

The drying chamber assembly 10b for drying battery electrodes shown in Figure 2a comprises a drying chamber 1 having an entry port A for an electrode foil F and an exit port B for the electrode foil F, a solvent collector 2, and a heater 3. The drying chamber assembly 10b also comprises an exhaust duct 4 configured to lead fluid from the drying chamber 1 to the solvent collector 2, a supply duct 5 configured to lead fluid from the solvent collector 2 to the heater 3 and an inlet duct 6 configured to lead fluid to the drying chamber 1 from the heater 3. The drying chamber assembly 10b further comprises a first by-pass duct 7 configured to lead fluid from the inlet duct 6 to the exhaust duct 4, and a first valve assembly 9.1 configured to control the flow from the heater 3 to the drying chamber 1 and to the exhaust duct 4. The first valve assembly 9.1 is able to redirect the flow of hot fluid from the heater 3 to the exhaust duct 4 thereby by-passing the drying chamber 1.

During operation of the drying chamber assembly 10b, an electrode foil F coated with a slurry comprising a solvent, binders and electrode material, enters the drying chamber 1 at entry port A. In the drying chamber 1, the electrode foil F is dried by hot fluid, usually hot air, entering the drying chamber via the inlet duct 6. Dried electrode foil F exits the drying chamber 1 at exit port B. The hot fluid, usually hot air, comprising evaporated solvent from the slurry, exits the drying chamber 1 through exhaust duct 4 and is fed to the solvent collector 2. In the solvent collector 2, the solvent is separated from the drying fluid and exits the solvent collector 2 through the solvent outlet C. The solvent may be recycled and reused for preparing new slurry. From the solvent collector 2 the drying fluid is fed through the supply duct 5 to the heater 3, where the drying fluid is heated and again fed through the inlet duct 6 to the drying chamber 1. In case of an interruption of the operation of the drying chamber 1, the flow of hot fluid is redirected via the first valve assembly 9.1 from the inlet duct 6 to the exhaust duct 4 via the first by-pass duct 7, thus by-passing the drying chamber 1. This is advantageous, since the drying fluid and the exhaust duct 4, the supply duct 5 and the inlet duct 6 do not cool down substantially during the time it takes until the drying chamber 1 is fully operational again. This has the effect that, when the drying chamber 1 is restarted, the time period from start to the time point where an electrode can be dried with acceptable results (also referred to as the ramp- up time) is shorter compared to the ramp-up time for the conventional drying chamber assembly 10a described in Fig. 1, since the ducts do not have to be reheated. Typically, the time period needed to reheat the drying chamber assembly is reduced to 20 to 30 minutes.

The first by-pass duct 7 is connected to the inlet duct 6 at a position located at a distance DI from the drying chamber 1. Preferably, the distance DI is as short as possible in order to minimize the length of inlet duct 6 that is by-passed and thus allowed to cool down during interruption of the operation of the drying chamber 1. Preferably, the distance DI is less than 20 % of the length of the inlet duct 6, such as less than 15 % of the length of the inlet duct 6, such as less than 10 % of the length of the inlet duct 6, such as less than 5 % of the length of the inlet duct 6, such as less than 3 % of the length of the inlet duct 6.

The first by-pass duct 7 is connected to the exhaust duct 4 at a position located at a distance D2 from the drying chamber 1. Preferably, the distance D2 is as short as possible in order to minimize the length of exhaust duct 4 that is by-passed and thus allowed to cool down during interruption of the operation of the drying chamber 1. Preferably, the distance D2 is less than 20 % of the length of the exhaust duct 4, such as less than 15 % of the length of the exhaust duct 4, such as less than 10 % of the length of the exhaust duct 4, such as less than 5 % of the length of the exhaust duct 4, such as less than 3 % of the length of the exhaust duct 4.

The first valve assembly 9.1 may comprise one or two valves. Typically, a valve of the first valve assembly 9.1 is a so-called damper. A damper valve allows for accurate directional flow control.

In the specific embodiment wherein the first valve assembly 9.1 comprises one valve, the valve may be positioned at a location where first by-pass duct 7 connects to inlet duct 6 and being able to adjust the flow of the fluid to the drying chamber 1 and to the first by-pass duct 7. Alternatively, the valve may positioned “above” the connection between the first by-pass duct 7 and the inlet duct 6 (i.e. on the drying chamber side of the connection). When the valve is closed, the hot fluid from the heater 3 flows through the first by-pass duct 7 to the exhaust duct 4, thereby by-passing the drying chamber 1. When the valve is open, fluid flows into the drying chamber 1, but also through the first by-pass duct 7. This has the effect that the first by-pass duct 7 is always hot, which will not lead to a substantial temperature decrease of the hot fluid when the fluid is redirect through the first by-pass duct 7 in the event of an interruption in the operation of the drying chamber 1, such as in the event of a foil break, maintenance or mending of broken parts. In the specific embodiment wherein the first valve assembly 9.1 comprises two valves, a first valve may be positioned “above” the connection between the first by-pass duct 7 and the inlet duct 6 (i.e. on the drying chamber side of the connection) and may regulate the flow of fluid to the drying chamber 1. A second valve may be positioned in the first by-pass duct 7 and may regulate the flow of fluid to the exhaust duct 4. When the first valve is open and the second valve is closed, the fluid from the heater 3 flows into the drying chamber 1. When the first valve is closed and the second valve is open, the fluid from the heater 3 flows through the first by-pass duct 7 to the exhaust duct 4, thereby by-passing the drying chamber 1. Further, the second valve can regulate the amount of fluid that passes through the first by-pass duct 7, such that a minor part of the fluid always passes through the first by-pass duct 7, having the effect that the first by-pass duct 7 is always hot, which will not lead to a temperature decrease of the hot fluid when the fluid is redirect through the first by-pass duct 7 in the event of an interruption in the operation of the drying chamber 1, such as in the event of a foil break, , maintenance or mending of broken parts.

Figure 2b illustrates another embodiment of the present disclosure. In addition to the features described for the drying chamber assembly 10b of Figure 2a, this embodiment further comprises a second valve assembly 9.2 configured to control the flow of fluid from the first by-pass duct 7 to the exhaust duct 4 and being able to allow flow of fluid from the heater 3 to the exhaust duct 4.

The second valve assembly 9.2 may comprise one or two valves. Typically, a valve of the second valve assembly 9.2 is a so-called damper. A damper valve allows for accurate directional flow control.

In the specific embodiment wherein the second valve assembly 9.2 comprises one valve, the valve may be positioned at a location where first by-pass duct 7 connects to exhaust duct 4 and being able to adjust the flow of the fluid to the exhaust duct 4. Alternatively, the valve may positioned “above” the connection between the first by-pass duct 7 and the exhaust duct 4 (i.e. on the drying chamber side of the connection). When the valve is open, fluid flows from the drying chamber 1 to the solvent collector 2 via the exhaust duct 4. When the valve is closed and the first valve assembly 9.1 is adjusted to allow flow of fluid from the heater 3 via the inlet duct 6 through the first by-pass duct 7 into the exhaust duct 4, the drying chamber 1 is effectively by-passed. In the specific embodiment wherein the second valve assembly 9.2 comprises two valves, a first valve may be positioned “above” the connection between the first by-pass duct 7 and the exhaust duct 4 (i.e. on the drying chamber side of the connection) and may regulate the flow of fluid from the drying chamber 1 to the solvent collector 2 via the exhaust duct 4. A second valve may be positioned in the first by-pass duct 7 and may regulate the flow of fluid to the exhaust duct 4 from the inlet duct 6. When the first valve is open and the second valve is closed, the fluid flows from the drying chamber 1 to the solvent collector 2 via the exhaust duct 4. When the first valve is closed and the second valve is open, the fluid from the heater 3 flows through the first by-pass duct 7 to the exhaust duct 4, provided the first valve assembly 9.1 is adjusted to allow the flow of fluid from the heater into the first by-pass duct 7, thereby effectively by-passing the drying chamber 1. Further, the second valve can regulate the amount of hot fluid that passes the first by-pass duct 7, such that a minor part of the fluid always passes through the first by-pass duct 7, having the effect that the first by-pass duct 7 is always hot, which will not lead to a temperature decrease of the hot fluid when the fluid is redirect through the first by-pass duct 7 in the event of an interruption in the operation of the drying chamber 1, such as in the event of a foil break, maintenance or mending of broken parts.

Figure 3a illustrates another embodiment of the present disclosure. In addition to the features described for the drying chamber assembly 10b of Figure 2a or of Fig 2b, this embodiment further comprises a second by-pass duct 8 configured to lead fluid from the exhaust duct 4 to the supply duct 5, and a third valve assembly 9.3 configured to control the flow of fluid from the exhaust duct 4 to the solvent collector 2 and to the supply duct 5. The third valve assembly 9.3 is able to redirect the flow of fluid from the exhaust duct 4 to the supply duct 5, thereby bypassing the solvent collector 2.

The second by-pass duct 8 is connected to the exhaust duct 4 at a position located at a distance D3 from the solvent collector 2. Preferably, the distance D3 is as short as possible in order to minimize the length of exhaust duct 4 that is by-passed and thus allowed to cool down during interruption of the operation of the drying chamber 1. Preferably, the distance D3 is less than 20 % of the length of the exhaust duct 4, such as less than 15 % of the length of the exhaust duct 4, such as less than 10 % of the length of the exhaust duct 4, such as less than 5 % of the length of the exhaust duct 4, such as less than 3 % of the length of the exhaust duct 4. The second by-pass duct 8 is connected to the supply duct 5 at a position located at a distance D4 from the solvent collector 2. Preferably, the distance D4 is as short as possible in order to minimize the length of supply duct 5 that is by-passed and thus allowed to cool down during interruption of the operation of the drying chamber 1. Preferably, the distance D4 is less than 20 % of the length of the supply duct 5, such as less than 15 % of the length of the supply duct 5, such as less than 10 % of the length of the supply duct 5, such as less than 5 % of the length of the supply duct 5, such as less than 3 % of the length of the supply duct 5.

The third valve assembly 9.3 may comprise one or two valves. Typically, a valve of the third valve assembly 9.3 is a so-called damper. A damper valve allows for accurate directional flow control.

In the specific embodiment wherein the third valve assembly 9.3 comprises one valve, the valve may be positioned at a location where second by-pass duct 8 connects to exhaust duct 4 and being able to adjust the flow of fluid to the solvent collector 2 and to the second by-pass duct 8. Alternatively, the valve may positioned “below” the connection between the second by-pass duct 8 and the exhaust duct 4 (i.e. on the solvent collector side of the connection). When the valve is closed, the fluid from the exhaust duct 4 flows through the second by-pass duct 8 to the supply duct 5, thereby by-passing the solvent collector 2. When the valve is open, fluid flows into the solvent collector 2, but also through the second by-pass duct 8. This has the effect that the second by-pass duct 8 is always warm, which will not lead to a substantial temperature decrease of the fluid when the fluid is redirect through the second by-pass duct 8 in the event of an interruption in the operation of the drying chamber 1, such as in the event of a foil break, maintenance or mending of broken parts.

In the specific embodiment wherein the third valve assembly 9.3 comprises two valves, a first valve may be positioned “below” the connection between the second by-pass duct 8 and the exhaust duct 4 (i.e. on the solvent collector side of the connection) and may regulate the flow of fluid to the solvent collector 2. A second valve may be positioned in the second by-pass duct 8 and may regulate the flow of fluid to the supply duct 5. When the first valve is open and the second valve is closed, the fluid flows from the exhaust duct 4 into the solvent collector 2. When the first valve is closed and the second valve is open, the fluid from the exhaust duct 4 flows through the second by-pass duct 8 to the supply duct 5, thereby by-passing the solvent collector 2. Further, the second valve can regulate the amount of fluid that passes through the second by-pass duct 8, such that a minor part of the fluid always passes through the second bypass duct 8, having the effect that the second by-pass duct 8 is always warm, which will not lead to a temperature decrease of the fluid when the fluid is redirect through the second bypass duct 8 in the event of an interruption in the operation of the drying chamber 1, such as in the event of a foil break, maintenance or mending of broken parts.

Figure 3b illustrates another embodiment of the present disclosure. In addition to the features described for the drying chamber assembly 10b of Figure 3a, this embodiment further comprises a fourth valve assembly 9.4 configured to control the flow of fluid from the second by-pass duct 8 to the supply duct 5 and being able to allow flow of fluid from the exhaust duct 4 to the supply duct 5.

The fourth valve assembly 9.4 may comprise one or two valves. Typically, a valve of the fourth valve assembly 9.4 is a so-called damper. A damper valve allows for accurate directional flow control.

In the specific embodiment wherein the fourth valve assembly 9.4 comprises one valve, the valve may be positioned at a location where second by-pass duct 8 connects to supply duct 5 and being able to adjust the flow to the supply duct 5. Alternatively, the valve may positioned between the solvent collector 2 and the connection between the second by-pass duct 8 and the supply duct 5 (i.e. on the solvent collector side of the connection). When the valve is open, fluid flows from the solvent collector 2 to the heater 3 via the supply duct 5. When the valve is closed and the third valve assembly 9.3 is adjusted to allow flow of fluid from the exhaust duct 4 to the second by-pass duct 8 into the supply duct 5, the solvent collector 2 is effectively bypassed.

In the specific embodiment wherein the fourth valve assembly 9.4 comprises two valves, a first valve may be positioned between the solvent collector 2 and the connection between the second by-pass duct 8 and the supply duct 5 (i.e. on the solvent collector side of the connection) and may regulate the flow of fluid from the solvent collector 2 to the heater 3 via the supply duct 5. A second valve may be positioned in the second by-pass duct 8 and may regulate the flow to the supply duct 5. When the first valve is open and the second valve is closed, the fluid flows from the solvent collector 2 to the heater 3 via the supply duct 5. When the first valve is closed and the second valve is open, the fluid from the exhaust duct 4 flows through the second bypass duct 8 to the supply duct 5, provided the third valve assembly 9.3 is adjusted to allow the flow of fluid from the exhaust duct 4 into the second by-pass duct 8, thereby effectively bypassing the solvent collector 2. Further, the second valve can regulate the amount of fluid that passes the second by-pass duct 8, such that a minor part of the fluid always passes through the second by-pass duct 8, having the effect that the second by-pass duct 8 is always warm, which will not lead to a temperature decrease of the fluid when the fluid is redirect through the second by-pass duct 8 in the event of an interruption in the operation of the drying chamber 1, such as in the event of a foil break, maintenance or mending of broken parts.

Figure 4a illustrates the pathway (dotted areas) for the fluid during operation of a drying chamber assembly 10b. The drying fluid is heated in the heater 3 and flows through the inlet duct 6 into the drying chamber 1. The drying fluid (comprising evaporated solvent) exits the drying chamber 1 and flows via the exhaust duct 4 into the solvent collector 2, where the solvent is separated from the drying fluid. The drying fluid exits the solvent collector 2 and flows via the supply duct 5 back to the heater 3. As explained above, a minor portion of the drying fluid may flow through the by-pass duct 7 and/or through the by-pass duct 8 also during operation of the drying chamber assembly 10b.

Figure 4b illustrates the pathway (dotted areas) for the fluid in the event of interruption in the function of the drying chamber 1, e.g. an electrode foil break. During an interruption in the function of the drying chamber 1, the valve assembly 9.1 and, if present, the valve assemblies 9.2, 9.3 and 9.4, are adjusted to by-pass the drying chamber 1 and optionally also the solvent collector 2. Figure 2b illustrates the case when both the drying chamber 1 and the solvent collector 2 are by-passed. The drying fluid is heated in the heater 3 and flows through the inlet duct 6 into the by-pass duct 7 to the exhaust duct 4. From the exhaust duct 4, the drying fluid enters the by-pass duct 8 and flows via the supply duct 5 back to the heater 3.

Method for reducing ramp-up time

The present disclosure also relates to a method for reducing ramp-up time in a drying chamber assembly 10b as described herein. The method comprises bypassing the drying chamber 1 by redirecting the flow of fluid from the heater 3 to the exhaust duct 4. This may be accomplished by regulating the valve assembly 9.1 and, optionally, if present, also the valve assembly 9.2, as described above. Typically, the ramp-up time is reduced to 4 to 3,5 hours, since the time-period for reheating the drying chamber assembly 10b is reduced to 20 to 30 minutes.

According to a specific embodiment, the method further comprises bypassing the solvent collector 2 by redirecting the flow of fluid from the exhaust duct 4 to the supply duct 5. This may be accomplished by regulating the valve assembly 9.3 and, optionally, if present, also the valve assembly 9.4, as described above.

Method for drying batery electrodes

The present disclosure also relates to a method for drying battery electrodes with hot fluid in a drying chamber 1. The drying chamber is configured to dry a coated electrode foil F entering the drying chamber at entry port A and exiting the drying chamber at exit port B. The method comprises the steps of feeding hot fluid to the drying chamber 1 from a heater 3 via an inlet duct 6, leading at least a portion of the flow of fluid from the drying chamber 1 to a solvent collector 2 via an exhaust duct 4, and leading fluid from the solvent collector 2 to the heater 3 via a supply duct 5. In the event of an interruption of the operation of the drying chamber 1 , the method comprises the step of bypassing the drying chamber 1 by redirecting the flow of fluid from the heater 3 to the exhaust duct 4 via a first by-pass duct 7. This may be accomplished by regulating the valve assembly 9.1 and, optionally, if present, also the valve assembly 9.2, as described above. In some cases, all of the fluid from the drying chamber 1 is led to a solvent collector 2 via an exhaust duct 4.

According to a specific embodiment, in the event of an interruption of the operation of the drying chamber, the method further comprises bypassing the solvent collector 2 by redirecting the flow of fluid from the exhaust duct 4 to the supply duct 5 via a second by-pass duct 8. This may be accomplished by regulating the valve assembly 9.3 and, optionally, if present, also the valve assembly 9.4, as described above.

Method for retrofitting a drying chamber assembly

The present disclosure also relates to a method for retrofitting a drying chamber assembly 10b for drying battery electrodes. The drying chamber assembly 10b comprises a drying chamber 1 having an entry port A for an electrode foil F and an exit port B for the electrode foil F, a solvent collector 2, a heater 3, an exhaust duct 4 configured to lead fluid from the drying chamber 1 to the solvent collector 2, a supply duct 5 configured to lead fluid from the solvent collector 2 to the heater 3, and an inlet duct 6 configured to lead fluid to the drying chamber 1 from the heater 3. The method comprises installing a first by-pass duct 7 configured to lead fluid from the from the inlet duct 6 to the exhaust duct 4, and a first valve assembly 9.1 configured to control the flow of fluid from the heater 3 to the drying chamber 1 and to the exhaust duct 4, the first valve assembly 9.1 being able to redirect the flow of fluid from the heater 3 to the exhaust duct 4 via the first by-pass duct 7, thereby by-passing the drying chamber 1.

According to a specific embodiment, the method further comprises installing a second by-pass duct 8 configured to lead fluid from the exhaust duct 4 to the supply duct 5, and a third valve assembly 9.3 configured to control the flow of fluid from the exhaust duct 4 to the solvent collector 2 and to the supply duct 5, the third valve assembly 9.3 being able to redirect the flow of fluid from the exhaust duct 4 to the supply duct 5 via the second by-pass duct 8, thereby bypassing the solvent collector 2.

Method of operating a drying chamber assembly

The present disclosure also relates to a method of operating a drying chamber assembly 10b for drying battery electrodes. The method comprises sensing if an electrode foil break has occurred in the drying chamber 1, and in the event of an electrode foil break: by-passing the drying chamber 1 by redirecting the flow of fluid from the heater 3 to the exhaust duct 4. This may be accomplished by regulating the valve assembly 9.1 and, optionally, if present, also the valve assembly 9.2, as described above.

In a specific embodiment, the method further comprises by-passing the solvent collector 2 by redirecting the flow of fluid from the exhaust duct 4 to the supply duct 5. This may be accomplished by regulating the valve assembly 9.3 and, optionally, if present, also the valve assembly 9.4, as described above.

Computer program

The present disclosure also relates to a computer program comprising instructions to cause the first valve assembly 9.1 and, optionally, the third valve assembly 9.3 to execute the steps of the method of operating a drying chamber assembly for drying battery electrodes as described above. In a specific embodiment, the computer program further comprises instructions to cause the second valve assembly and/or the fourth valve assembly to execute the steps of the method of operating a drying chamber assembly for drying battery electrodes as described above.

Use of a by-pass duct 7 in a drying chamber assembly

The present disclosure also relates to a use of a by-pass duct 7 in a drying chamber assembly 10b for drying battery electrodes, wherein the by-pass duct 7 is used to by-pass a drying chamber 1 in the event of an interruption of the operation of the drying chamber.

Modifications and other variants of the described embodiments will come to mind to ones skilled in the art having benefit of the teachings presented in the foregoing description and associated drawings. Therefore, it is to be understood that the embodiments are not limited to the specific example embodiments described in this disclosure and that modifications and other variants are intended to be included within the scope of this disclosure.

Furthermore, although specific terms may be employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. Therefore, persons skilled in the art would recognize numerous variations to the described embodiments that would still fall within the scope of the appended claims. As used herein, the terms “comprise/comprises” or “include/includes” do not exclude the presence of other elements or steps. Furthermore, although individual features may be included in different claims (or embodiments), these may possibly advantageously be combined, and the inclusion of different claims (or embodiments) does not imply that a certain combination of features is not feasible and/or advantageous. In addition, singular references do not exclude a plurality. Finally, reference numerals in the claims are provided merely as a clarifying example and should not be construed as limiting the scope of the claims in any way.