Electrochromic device with maximum local cell potential aligned with sense voltage

A method for controlling an electrochromic device, comprising:

• applying a constant supply current to the electrochromic device using at least two bus bars of the electrochromic device;
• determining an amount of charge transferred to the electrochromic device, as a function of time and current supplied to the electrochromic device;
• measuring a sense voltage using a first sense voltage pad of the electrochromic device;
• ceasing the applying the constant supply current, responsive to the sense voltage reaching a sense voltage limit;
• applying one of a variable voltage or a variable current to the electrochromic device using the bus bars to maintain the sense voltage at the sense voltage limit, responsive to the sense voltage reaching the sense voltage limit;
• and
• terminating the applying the variable voltage or the variable current to the electrochromic device, responsive to the determined amount of charge reaching a target amount of charge,
• wherein the electrochromic device comprises two electrically conductive layers each comprising a gradient in electrical resistance,
• wherein the sense voltage pad is coupled to one of the electrically conductive layers and is configured to measure a local cell potential at a sense voltage measurement position within the electrochromic device;
• and
• wherein the gradients in electrical resistance are configured to form a region comprising a maximum local cell potential approximately coinciding with the sense voltage measurement position.

A method comprising:

• applying a constant supply current to an electrochromic device, wherein the electrochromic device comprises:
• a first electrically conductive layer arranged on an inner surface of a first transparent substrate, wherein the first electrically conductive layer comprises a first gradient in resistance to the flow of electrical current through the first electrically conductive layer that varies as a function of position;
• a second electrically conductive layer arranged on an inner surface of a second transparent substrate, wherein the second electrically conductive layer comprises a second gradient in resistance to the flow of electrical current through the second electrically conductive layer that varies as a function of position;
• a first bus bar in contact with the first electrically conductive layer;
• a second bus bar in contact with the second electrically conductive layer;
• and
• a first sense voltage pad arranged on an inner surface of the first transparent substrate configured to measure a local cell potential at a sense voltage measurement position within the electrochromic device,
• wherein the first and second resistance gradients are configured to form a region comprising a maximum local cell potential approximately coinciding with the sense voltage measurement position, and
• wherein the constant supply current to the electrochromic device is applied using the first and second bus bars;
• determining an amount of charge transferred to the electrochromic device, as a function of time and current supplied to the electrochromic device;
• measuring a sense voltage using the first sense voltage pad of the electrochromic device;
• ceasing the applying the constant supply current, responsive to the sense voltage reaching a sense voltage limit;
• applying one of a variable voltage or a variable current to the electrochromic device using the bus bars to maintain the sense voltage at the sense voltage limit, responsive to the sense voltage reaching the sense voltage limit;
• and
• terminating the applying the variable voltage or the variable current to the electrochromic device, responsive to the determined amount of charge reaching a target amount of charge.

A method comprising:

• forming an electrochromic device comprising:
• forming a first electrically conductive layer arranged on an inner surface of a first transparent substrate, wherein the first electrically conductive layer comprises a first gradient in resistance to the flow of electrical current through the first electrically conductive layer that varies as a function of position;
• forming a second electrically conductive layer arranged on an inner surface of a second transparent substrate, wherein the second electrically conductive layer comprises a second gradient in resistance to the flow of electrical current through the second electrically conductive layer that varies as a function of position;
• forming a first bus bar in contact with the first electrically conductive layer;
• forming a second bus bar in contact with the second electrically conductive layer;
• and
• forming a first sense voltage pad arranged on an inner surface of the first transparent substrate configured to measure a local cell potential at a sense voltage measurement position within the electrochromic device,
• wherein the first and second resistance gradients are configured to form a region comprising a maximum local cell potential approximately coinciding with the sense voltage measurement position;
• applying a constant supply current to the electrochromic device using the first and second bus bars of the electrochromic device;
• determining an amount of charge transferred to the electrochromic device, as a function of time and current supplied to the electrochromic device;
• measuring a sense voltage using a first sense voltage pad of the electrochromic device;
• ceasing the applying the constant supply current, responsive to the sense voltage reaching a sense voltage limit;
• applying one of a variable voltage or a variable current to the electrochromic device using the bus bars to maintain the sense voltage at the sense voltage limit, responsive to the sense voltage reaching the sense voltage limit;
• and
• terminating the applying the variable voltage or the variable current to the electrochromic device, responsive to the determined amount of charge reaching a target amount of charge.

A method for controlling an electrochromic device, comprising:

• applying a constant supply current to the electrochromic device using at least two bus bars of the electrochromic device;
• measuring a sense voltage using a first sense voltage pad of the electrochromic device;
• ceasing the applying the constant supply current, responsive to the sense voltage reaching a sense voltage limit;
• applying one of a variable voltage or a variable current to the electrochromic device using the bus bars to maintain the sense voltage at the sense voltage limit, responsive to the sense voltage reaching the sense voltage limit;
• and
• terminating the applying the variable voltage or the variable current to the electrochromic device, responsive to a trigger, wherein the trigger optionally comprises a determined amount of charge reaching a target amount of charge, a time limit being reached, a current limit being reached, or a current flow dropping below a predetermined threshold,
• wherein the electrochromic device comprises two electrically conductive layers each comprising a gradient in electrical resistance,
• wherein the sense voltage pad is coupled to one of the electrically conductive layers and is configured to measure a local cell potential at a sense voltage measurement position within the electrochromic device;
• and
• wherein the gradients in electrical resistance are configured to form a region comprising a maximum local cell potential approximately coinciding with the sense voltage measurement position.

A method comprising:

• modeling resistance gradients of electrically conductive layers of an electrochromic device with two bus bars using a finite element model, wherein the modeling comprises:
• starting with initial resistance gradients of the electrically conductive layers;
• defining a first region comprising a sense voltage pad;
• providing a target local cell potential map comprising a target local cell potential value across an active area of the electrochromic device, and a maximum local cell potential within the first region;
• using the finite element model to produce final resistance gradients of the electrically conductive layers to form a final local cell potential map, wherein a difference between the final local cell potential map and the target local cell potential map is minimized by the finite element model, and wherein the final resistance gradients comprise gradients in an x-direction that is approximately perpendicular to the bus bars of the electrochromic device and in a y-direction that is perpendicular to the x-direction.