METHOD FOR FORMING FLOW CHANNEL ON METAL BIPOLAR PLATE OF FUEL CELL

Abstract

A method for forming a flow channel on a metal bipolar plate of a fuel cell includes: pre-treating a metal polar plate; subjecting the metal polar plate to low-temperature heating; forming a flow channel on the metal polar plate by rolling; cutting an inlet and outlet for gas and cooling liquid on the metal polar plate; performing surface treatment on the metal polar plate; bonding two metal polar plates to form a metal bipolar plate; and trimming the metal bipolar plate. The flow channel is formed by two pre-forming and one truing, and design parameters of punches and dies of the rollers used are determined by calculation models.

Claims

1. A method for forming a flow channel on a metal bipolar plate of a fuel cell, comprising: pre-treating a metal polar plate; subjecting the metal polar plate to low-temperature heating; forming a flow channel on the metal polar plate by rolling; cutting a gas inlet, a gas outlet, a cooling liquid inlet and a cooling liquid outlet on the metal polar plate; subjecting the metal polar plate to surface treatment; bonding the metal polar plate with another metal polar plate treated by the above steps to form a metal bipolar plate; and trimming the metal bipolar plate; wherein the step of “forming a flow channel on the metal polar plate by rolling” is performed through steps of: performing pre-forming twice on the metal polar plate sequentially using a pair of first rollers and a pair of second rollers; and performing truing once using a pair of truing rollers to form the flow channel on the metal polar plate; and design parameters of a first punch and a first die of each of the pair of first rollers used in a first pre-forming and design parameters of a second punch and a second die of each of the pair of second rollers used in a second pre-forming are determined through the following steps: (1) determining an inclination length l.sub.11, a draft angle β.sub.11 and a depth h.sub.11 of the first punch by a first calculation model: $\{\begin{array}{c}{l}_{11}=\left(r_{11}+k_{1}t\right)\tan \frac{{\alpha }_{11}}{2}\\ {\beta }_{11}=90°-{\alpha }_{11}\\ h_{11}=r_{11}\left(1-\cos {\alpha }_{11}\right)+\left(r_{11}+k_{1}t\right)\tan \frac{{\alpha }_{11}}{2}\times \sin {\alpha }_{11}\end{array};$ wherein r.sub.11 is an arc radius of the first punch; α.sub.11 is half of an arc included angle of the first punch; t is a thickness of the metal polar plate; and k.sub.1 is a ratio of a thickness of the metal polar plate after the first pre-forming to a thickness of the metal polar plate before the first pre-forming, and 0<k.sub.1<1; and determining an inclination length l.sub.12, a draft angle β.sub.12, a depth h.sub.12 and a horizontal length l.sub.1 of the first die by a second calculation model: $\{\begin{array}{c}{l}_{12}=\left(r_{12}+k_{1}t\right)\tan \frac{{\alpha }_{12}}{2}\\ {\beta }_{12}=90°-{\alpha }_{12}\\ h_{12}=r_{12}\left(1-\cos {\alpha }_{12}\right)+\left(r_{12}+k_{1}t\right)\tan \frac{{\alpha }_{12}}{2}\times \sin {\alpha }_{12}\\ l_1=2\left(r_{12}+k_{1}t\right)\tan \frac{{\alpha }_{12}}{2}\end{array};$ wherein r.sub.12 is an arc radius of the first die; α.sub.12 is an arc included angle of the first die; t is the thickness of the metal polar plate; and k.sub.1 is the ratio of the thickness of the metal polar plate after the first pre-forming to the thickness of the metal polar plate before the first pre-forming, and 0<k.sub.1<1; and (2) determining an inclination length l.sub.21, an arc radius r.sub.21, a draft angle fill and a depth h.sub.21 of the second punch by a third calculation model: $\{\begin{array}{c}{r}_{21}=\frac{k_1{\alpha }_{11}}{k_2{\alpha }_{21}}\times \left(r_{11}+\frac{k_{1}t}{2}\right)-\frac{k_{2}t}{2}\\ l_{21}=\left(r_{21}+k_{2}t\right)\tan \frac{{\alpha }_{21}}{2}\\ {\beta }_{21}=90°-{\alpha }_{21}\\ h_{21}=r_{21}\left(1-\cos {\alpha }_{21}\right)+\left(r_{21}+k_{2}t\right)\tan \frac{{\alpha }_{21}}{2}\times \sin {\alpha }_{21}\end{array};$ wherein r.sub.11 is the arc radius of the first punch; α.sub.11 is half of the arc included angle of the first punch; α.sub.21 is half of an arc included angle of the second punch; t is the thickness of the metal polar plate; k.sub.1 is the ratio of the thickness of the metal polar plate after the first pre-forming to the thickness of the metal polar plate before the first pre-forming, and 0<k.sub.1<1; and k.sub.2 is a ratio of a thickness of the metal polar plate after the second pre-forming to the thickness of the metal polar plate after the first pre-forming, and 0<k.sub.2<1; and determining an inclination length l.sub.22, an arc radius r.sub.22, a draft angle β.sub.22, a depth h.sub.22 and a horizontal length l.sub.1 of the second die by a fourth calculation model: $\{\begin{array}{c}{r}_{22}=\frac{k_1{\alpha }_{12}}{k_2{\alpha }_{22}}\times \left(r_{12}+\frac{k_{1}t}{2}\right)-\frac{k_{2}t}{2}\\ l_{22}=\left(r_{22}+k_{2}t\right)\tan \frac{{\alpha }_{22}}{2}\\ {\beta }_{22}=90°-{\alpha }_{22}\\ h_{22}=r_{22}\left(1-\cos {\alpha }_{22}\right)+\left(r_{22}+k_{2}t\right)\tan \frac{{\alpha }_{22}}{2}\times \sin {\alpha }_{22}\\ l_2=2\left(r_{22}+k_{2}t\right)\tan \frac{{\alpha }_{22}}{2}\end{array};$ wherein r.sub.12 is the arc radius of the first die; α.sub.12 is the arc included angle of the first die; α.sub.22 is an arc included angle of the second die; t is the thickness of the metal polar plate; k.sub.1 is the ratio of the thickness of the metal polar plate after the first pre-forming to the thickness of the metal polar plate before the first pre-forming, and 0<k.sub.1<1; and k.sub.2 is the ratio of the thickness of the metal polar plate after the second pre-forming to the thickness of the metal polar plate after the first pre-forming, and 0<k.sub.2<1.

2. The method of claim 1, wherein design parameters of a third punch and a third die of each of the pair of truing rollers are determined through the following steps: determining an inclination length l.sub.31, an arc radius r.sub.31, a draft angle β.sub.31 and a depth h.sub.31 of the third punch by a fifth calculation model: $\{\begin{array}{c}{r}_{31}=\frac{r_{21}{k}_2{\alpha }_{21}}{k_3{\alpha }_{31}}+\frac{k_2^{2}t{\alpha }_{21}}{2k_3{\alpha }_{31}}-\frac{90°\left(s+c\right)}{\pi {\alpha }_{31}}-\frac{k_{3}t}{2}\\ l_{31}=\left(r_{31}+k_{3}t\right)\tan \frac{{\alpha }_{31}}{2}+s\\ {\beta }_{31}=90°-{\alpha }_{31}\\ h_{31}=r_{31}\left(1-\cos {\alpha }_{31}\right)+\left(r_{31}+k_{3}t\right)\tan \frac{{\alpha }_{31}}{2}\times \sin {\alpha }_{32}+s\cos {\beta }_{31}\end{array};$ wherein r.sub.21 is the arc radius of the second punch; α.sub.21 is half of the arc included angle of the second punch; α.sub.31 is half of an arc included angle of the third punch; s is an inclination length of the third punch and the third die for elongating the metal polar plate; c is a horizontal length of the third punch and the third die for elongating the metal polar plate; t is the thickness of the metal polar plate; k.sub.2 is the ratio of the thickness of the metal polar plate after the second pre-forming to the thickness of the metal polar plate after the first pre-forming, and 0<k.sub.2<1; and k.sub.3 is a ratio of a thickness of the metal polar plate after the truing to the thickness of the metal polar plate after the second pre-forming, and 0<k.sub.3<1; and determining an inclination length l.sub.32, an arc radius r.sub.32, a draft angle β.sub.32, a depth h.sub.32 and a horizontal length l.sub.3 of the third die by a sixth calculation model: $\{\begin{array}{c}{r}_{32}=\frac{r_{22}{k}_2{\alpha }_{22}}{k_3{\alpha }_{32}}+\frac{k_2^{2}t{\alpha }_{22}}{2k_3{\alpha }_{32}}-\frac{90°\left(s+c\right)}{\pi {\alpha }_{32}}-\frac{k_{3}t}{2}\\ l_{32}=\left(r_{32}+k_{3}t\right)\tan \frac{{\alpha }_{32}}{2}+s\\ {\beta }_{32}=90°-{\alpha }_{32}\\ h_{32}=r_{32}\left(1-\cos {\alpha }_{32}\right)+\left(r_{32}+k_{3}t\right)\tan \frac{{\alpha }_{32}}{2}\times \sin {\alpha }_{32}+s\cos {\beta }_{32}\\ l_3=2\left(r_{31}+k_{3}t\right)\tan \frac{{\alpha }_{31}}{2}+c\end{array};$ wherein r.sub.22 is the arc radius of the second die; α.sub.22 is the arc included angle of the second die; α.sub.32 is an arc included angle of the third die; s is the inclination length of the third punch and the third die for elongating the metal polar plate; c is the horizontal length of the third punch and the third die for elongating the metal polar plate; t is the thickness of the metal polar plate; k.sub.2 is the ratio of the thickness of the metal polar plate after the second pre-forming to the thickness of the metal polar plate after the first pre-forming, and 0<k.sub.2<1; and k.sub.3 is the ratio of the thickness of the metal polar plate after the truing to the thickness of the metal polar plate after the second pre-forming, and 0<k.sub.3<1.

3. The method of claim 1, wherein a model for calculating a depth h, a width d, a spine width w and a fillet angle r of the flow channel of the metal polar plate is shown as follows: $\{\begin{array}{c}r=\frac{r_{21}{k}_2{\alpha }_{21}}{k_3{\alpha }_{31}}+\frac{k_2^{2}t{\alpha }_{21}}{2k_3{\alpha }_{31}}-\frac{90°\left(s+c\right)}{\pi {\alpha }_{31}}-\frac{k_{3}t}{2}\\ h=r\left(1-\cos {\alpha }_{31}\right)+\left(r+k_{3}t\right)\tan \frac{{\alpha }_{31}}{2}\times \sin {\alpha }_{32}+s\cos {\beta }_{31}\\ w=2\left(r+k_{3}t\right)\sin {\alpha }_{31}+c\\ d=2s\sin {\beta }_{31}+2r\sin {\alpha }_{31}+c\end{array};$ wherein r.sub.21 is the arc radius of the second punch; α.sub.21 is half of the arc included angle of the second punch; α.sub.31 is half of an arc included angle of a punch of each of the pair of truing rollers; s is an inclination length of the punch and a die of each of the pair of truing rollers for elongating the metal polar plate; c is a horizontal length of the punch and the die of each of the pair of truing rollers for elongating the metal polar plate; t is the thickness of the metal polar plate; k.sub.2 is the ratio of the thickness of the metal polar plate after the second pre-forming to the thickness of the metal polar plate after the first pre-forming, and 0<k.sub.2<1; and k.sub.3 is a ratio of a thickness of the metal polar plate after the truing to the thickness of the metal polar plate after the second pre-forming, and 0<k.sub.3<1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG. 1 is a flow chart of a method for forming a flow channel on a metal bipolar plate according to an embodiment of the present disclosure;

[0033] FIG. 2 schematically depicts parameters of a punch and a die of a roller used in the first pre-forming process;

[0034] FIG. 3 schematically depicts parameters of a punch and a die of a roller used in the second pre-forming process;

[0035] FIG. 4 schematically depicts parameters of a punch and a die of a roller used in the truing process;

[0036] FIG. 5 schematically depicts the first pre-forming process;

[0037] FIG. 6 schematically depicts the second pre-forming process;

[0038] FIG. 7 schematically depicts the flow channels on the metal polar plate of the present disclosure after the second pre-forming process;

[0039] FIG. 8 schematically depicts the truing of the flow channels of the metal polar plate of the present disclosure; and

[0040] FIG. 9 schematically depicts the formed flow channels of the metal polar plate of the present disclosure.

[0041] In the drawings, 1, straightening and feeding metal polar plate; 2, thinning the metal polar plate; 3, straightening the metal polar plate; 4; cleaning the metal polar plate; 5, detecting thickness of the metal polar plate; 6, low-temperature heating the metal polar plate; 7, rolling the metal polar plate; 8, cutting the metal polar plate; 9, performing surface treatment on the metal polar plate; 10, bonding two metal polar plates to form a metal bipolar plate; and 11, trimming the metal bipolar plate.

DETAILED DESCRIPTION OF EMBODIMENTS

[0042] The disclosure will be clearly described below with reference to the accompanying drawings and embodiments.

[0043] As shown in FIG. 1, an embodiment of the disclosure provides a method for forming a flow channel on a metal bipolar plate of a fuel cell, which includes: (1) straightening and feeding metal polar plate; (2) thinning the metal polar plate; (3) straightening the metal polar plate; (4) cleaning the metal polar plate; (5) detecting thickness of the metal polar plate; (6) low-temperature heating the metal polar plate; (7) rolling the metal polar plate in an insulation device; (8) cutting the metal polar plate; (9) performing surface treatment on the metal polar plate; (10) bonding two metal polar plates to form a metal bipolar plate; and (11) trimming the metal bipolar plate.

[0044] As show in FIGS. 5-8, the metal polar plate is rolled from a middle of a width of the metal polar plate to two sides thereof to form flow channels, and a flow channel is formed by two pre-forming and one truing. The first pre-forming is performed for a first flow channel in center line of the metal polar plate by a first pair of rollers. The second pre-forming is performed on the first flow channel by a second pair of rollers, meanwhile, the first pre-forming is performed for second flow channels at a symmetrical position of the first flow channel on left and right equidistance. The second pre-forming is performed on the second flow channels by a third pair of rollers, meanwhile, the first pre-forming is performed for third flow channels at a symmetrical position of the first flow channel on twice the left and right equidistance, and so on. As a consequence, all of the low channels of the metal polar plate are performed two pre-formed. After the above steps, a truing is performed to all of the low channels by a pair of truing rollers to form the flow channel on the metal polar plate.

[0045] As shown in FIGS. 2 and 3, design parameters of a first punch and a first die of each first roller used in a first pre-forming and design parameters of a second punch and a second die of each second roller used in a second pre-forming are determined through the following steps.

[0046] (1) An inclination length l.sub.11, a draft angle β.sub.11 and a depth h.sub.11 of the first punch are determined by a first calculation model:

[00008]$\{\begin{array}{c}{l}_{11}=\left(r_{11}+k_{1}t\right)\tan \frac{{\alpha }_{11}}{2}\\ {\beta }_{11}=90°-{\alpha }_{11}\\ h_{11}=r_{11}\left(1-\cos {\alpha }_{11}\right)+\left(r_{11}+k_{1}t\right)\tan \frac{{\alpha }_{11}}{2}\times \sin {\alpha }_{11}\end{array};$

[0047] where r.sub.11 is an arc radius of the first punch; α.sub.11 is half of an arc included angle of the first punch; t is a thickness of the metal polar plate; and k.sub.1 is a ratio of a thickness of the metal polar plate after the first pre-forming to a thickness of the metal polar plate before the first pre-forming, and 0<k.sub.1<1.

[0048] An inclination length l.sub.12, a draft angle β.sub.12, a depth h.sub.12 and a horizontal length l.sub.1 of the first die are determined by a second calculation model:

[00009]$\{\begin{array}{c}{l}_{12}=\left(r_{12}+k_{1}t\right)\tan \frac{{\alpha }_{12}}{2}\\ {\beta }_{12}=90°-{\alpha }_{12}\\ h_{12}=r_{12}\left(1-\cos {\alpha }_{12}\right)+\left(r_{12}+k_{1}t\right)\tan \frac{{\alpha }_{12}}{2}\times \sin {\alpha }_{12}\\ l_1=2\left(r_{12}+k_{1}t\right)\tan \frac{{\alpha }_{12}}{2}\end{array};$

[0049] where r.sub.12 is an arc radius of the first die; α.sub.12 is an arc included angle of the first die; t is the thickness of the metal polar plate; and k.sub.1 is the ratio of the thickness of the metal polar plate after the first pre-forming to the thickness of the metal polar plate before the first pre-forming, and 0<k.sub.1<1.

[0050] (2) An inclination length l.sub.21, an arc radius r.sub.21, a draft angle fill and a depth h.sub.21 of the second punch are determined by a third calculation model:

[00010]$\{\begin{array}{c}{r}_{21}=\frac{k_1{\alpha }_{11}}{k_2{\alpha }_{21}}\times \left(r_{11}+\frac{k_{1}t}{2}\right)-\frac{k_{2}t}{2}\\ l_{21}=\left(r_{21}+k_{2}t\right)\tan \frac{{\alpha }_{21}}{2}\\ {\beta }_{21}=90°-{\alpha }_{21}\\ h_{21}=r_{21}\left(1-\cos {\alpha }_{21}\right)+\left(r_{21}+k_{2}t\right)\tan \frac{{\alpha }_{21}}{2}\times \sin {\alpha }_{21}\end{array};$

[0051] where r.sub.11 is the arc radius of the first punch; α.sub.11 is half of the arc included angle of the first punch; α.sub.21 is half of an arc included angle of the second punch; t is the thickness of the metal polar plate; k.sub.1 is the ratio of the thickness of the metal polar plate after the first pre-forming to the thickness of the metal polar plate before the first pre-forming, and 0<k.sub.1<1; k.sub.2 is a ratio of a thickness of the metal polar plate after the second pre-forming to the thickness of the metal polar plate after the first pre-forming, and 0<k.sub.2<1.

[0052] An inclination length l.sub.22, an arc radius r.sub.22, a draft angle β.sub.22, a depth h.sub.22 and a horizontal length l.sub.1 of the second die are determined by a fourth calculation model:

[00011]$\{\begin{array}{c}{r}_{22}=\frac{k_1{\alpha }_{12}}{k_2{\alpha }_{22}}\times \left(r_{12}+\frac{k_{1}t}{2}\right)-\frac{k_{2}t}{2}\\ l_{22}=\left(r_{22}+k_{2}t\right)\tan \frac{{\alpha }_{22}}{2}\\ {\beta }_{22}=90°-{\alpha }_{22}\\ h_{22}=r_{22}\left(1-\cos {\alpha }_{22}\right)+\left(r_{22}+k_{2}t\right)\tan \frac{{\alpha }_{22}}{2}\times \sin {\alpha }_{22}\\ l_2=2\left(r_{22}+k_{2}t\right)\tan \frac{{\alpha }_{22}}{2}\end{array};$

[0053] where r.sub.12 is the arc radius of the first die. α.sub.12 is the arc included angle of the first die; α.sub.22 is an arc included angle of the second die; t is the thickness of the metal polar plate; k.sub.1 is the ratio of the thickness of the metal polar plate after the first pre-forming to the thickness of the metal polar plate before the first pre-forming, and 0<k.sub.1<1; k.sub.2 is the ratio of the thickness of the metal polar plate after the second pre-forming to the thickness of the metal polar plate after the first pre-forming, and 0<k.sub.2<1.

[0054] As shown in FIG. 4, design parameters of a third punch and a third die of each of the pair of truing rollers are determined through the following steps.

[0055] An inclination length l.sub.31, an arc radius r.sub.31, a draft angle β.sub.31 and a depth h.sub.31 of the third punch are determined by a fifth calculation model:

[00012]$\{\begin{array}{c}{r}_{31}=\frac{r_{21}{k}_2{\alpha }_{21}}{k_3{\alpha }_{31}}+\frac{k_2^{2}t{\alpha }_{21}}{2k_3{\alpha }_{31}}-\frac{90°\left(s+c\right)}{\pi {\alpha }_{31}}-\frac{k_{3}t}{2}\\ l_{31}=\left(r_{31}+k_{3}t\right)\tan \frac{{\alpha }_{31}}{2}+s\\ {\beta }_{31}=90°-{\alpha }_{31}\\ h_{31}=r_{31}\left(1-\cos {\alpha }_{31}\right)+\left(r_{31}+k_{3}t\right)\tan \frac{{\alpha }_{31}}{2}\times \sin {\alpha }_{32}+s\cos {\beta }_{31}\end{array};$

[0056] where r.sub.21 is the arc radius of the second punch; α.sub.21 is half of the arc included angle of the second punch; α.sub.31 is half of an arc included angle of the third punch; s is an inclination length of the third punch and the third die for elongating the metal polar plate; c is a horizontal length of the third punch and the third die for elongating the metal polar plate; t is the thickness of the metal polar plate; k.sub.2 is the ratio of the thickness of the metal polar plate after the second pre-forming to the thickness of the metal polar plate after the first pre-forming, and 0<k.sub.2<1; and k.sub.3 is a ratio of a thickness of the metal polar plate after the truing to the thickness of the metal polar plate after the second pre-forming, and 0<k.sub.3<1.

[0057] An inclination length l.sub.32, an arc radius r.sub.32, a draft angle β.sub.32, a depth h.sub.32 and a horizontal length l.sub.3 of the third die are determined by a sixth calculation model:

[00013]$\{\begin{array}{c}{r}_{32}=\frac{r_{22}{k}_2{\alpha }_{22}}{k_3{\alpha }_{32}}+\frac{k_2^{2}t{\alpha }_{22}}{2k_3{\alpha }_{32}}-\frac{90°\left(s+c\right)}{\pi {\alpha }_{32}}-\frac{k_{3}t}{2}\\ l_{32}=\left(r_{32}+k_{3}t\right)\tan \frac{{\alpha }_{32}}{2}+s\\ {\beta }_{32}=90°-{\alpha }_{32}\\ h_{32}=r_{32}\left(1-\cos {\alpha }_{32}\right)+\left(r_{32}+k_{3}t\right)\tan \frac{{\alpha }_{32}}{2}\times \sin {\alpha }_{32}+s\cos {\beta }_{32}\\ l_3=2\left(r_{31}+k_{3}t\right)\tan \frac{{\alpha }_{31}}{2}+c\end{array};$

[0058] where r.sub.22 is the arc radius of the second die; α.sub.22 is the arc included angle of the second die; α.sub.32 is an arc included angle of the third die; s is the inclination length of the third punch and the third die for elongating the metal polar plate; c is the horizontal length of the third punch and the third die for elongating the metal polar plate; t is the thickness of the metal polar plate; k.sub.2 is the ratio of the thickness of the metal polar plate after the second pre-forming to the thickness of the metal polar plate after the first pre-forming, and 0<k.sub.2<1; and k.sub.3 is the ratio of the thickness of the metal polar plate after the truing to the thickness of the metal polar plate after the second pre-forming, and 0<k.sub.3<1.

[0059] As shown in FIG. 9, a model for calculating a depth h, a width d, a spine width w and a fillet angle r of the flow channel of the metal polar plate is shown as follows:

[00014]$\{\begin{array}{c}r=\frac{r_{21}{k}_2{\alpha }_{21}}{k_3{\alpha }_{31}}+\frac{k_2^{2}t{\alpha }_{21}}{2k_3{\alpha }_{31}}-\frac{90°\left(s+c\right)}{\pi {\alpha }_{31}}-\frac{k_{3}t}{2}\\ h=r\left(1-\cos {\alpha }_{31}\right)+\left(r+k_{3}t\right)\tan \frac{{\alpha }_{31}}{2}\times \sin {\alpha }_{32}+s\cos {\beta }_{31}\\ w=2\left(r+k_{3}t\right)\sin {\alpha }_{31}+c\\ d=2s\sin {\beta }_{31}+2r\sin {\alpha }_{31}+c\end{array};$

[0060] where r.sub.21 is the arc radius of the second punch; α.sub.21 is half of the arc included angle of the second punch; α.sub.31 is half of the arc included angle of the third punch; s is the inclination length of the third punch and the third die for elongating the metal polar plate; c is a horizontal length of the third punch and the third die for elongating the metal polar plate; t is the thickness of the metal polar plate; k.sub.2 is the ratio of the thickness of the metal polar plate after the second pre-forming to the thickness of the metal polar plate after the first pre-forming, and 0<k.sub.2<1; and k.sub.3 is the ratio of the thickness of the metal polar plate after the truing to the thickness of the metal polar plate after the second pre-forming, and 0<k.sub.3<1.

[0061] A metal anode plate and a metal cathode plate with straight flow channels or S-shaped flow channels can be manufactured by the forming method provided herein.